Raspberry Pi 4 RAM Upgrade - Tutorial🤫

If you need a repair or upgrade of a device, please follow this link: rb.gy/v6izn
Here is the link to my Patreon if you want to support what I am doing:
/ madedoctor
There is a link to the Raspberry Pi forum topic where different memory is listed and discussed.
forums.raspberrypi.com/viewto...
Below are the chip codes and links for each one where they can be purchased.
Micron D9WHZ | MT53D512M32D2DS-053 WT:D - 2GB Chip : rb.gy/1akj
Micron D9WHV | MT53D1024M32D4DT-053 WT:D - 4GB Chip : rb.gy/1q6d
Micron D9ZCL | MT53E2G32D4NQ-046 WT:A - 8GB Chip : rb.gy/agrf
These are the tools I am using:
Microscope - Amscope SM-4NTP with x0.5 Barlow lens
Amscope: amscope.com/products/c-sm-4ntp
Amazon: www.shorturl.at/fgy56
SM05 - 0.5x Barlow lens:
Amscope: amscope.com/products/sm05
Amazon: www.shorturl.at/lvCGZ
Soldering station - JCID AIXUN T3B with T210 Handle:
Aliexpress: rb.gy/hwql
Hot air station - ATTEN ST-862D:
Aliexpress: rb.gy/sz2z | Amazon: www.shorturl.at/IOTV1
Tweezers:
Aliexpress: rb.gy/ycgl
Aliexpress: rb.gy/3gwd
Rosin atomizer:
Aliexpress: rb.gy/ce4x
Board holder - T26:
Aliexpress: rb.gy/k2pv
Fume extractor - Aliexpress: rb.gy/83sl
Email for contact: [e-mail]
Flux - Aliexpress: rb.gy/dicav
Solder wick - Aliexpress: rb.gy/ykt8y
Different stencils I use:
Aliexpress: rb.gy/mqewwu
Aliexpress: rb.gy/nvzfvs
Aliexpress: rb.gy/axg9ut
Aliexpress: rb.gy/dyhkj2
Email for contacts: [e-mail]

[@OnnieKoski]

I may never actually do it, but it was awesome to see it be done. GREAT WORK!

[@lantrick]

Virtually no one will do this.

[@screen-protector]

Just an advice for those who'll do it their first times. Guys, you can make dots with a marker before removing the ram chip. When using packaging QFN type you have guides, but with RAM no, not always at least. So, worth making guides yourself. It's SUPER easy to make a mistake. I micro solder only for over 2 years and I can do it, but still no expert because it's only a part of what I'm doing. I can't practise each and every day, I fix all household electronics. But, if you don't have a practise, at least you can have these guides you've made ;).

[@note2tee]

Permanent black marker don't work, they just dissolved in flux when heated up😂

[@ikemkrueger]

@@note2tee Slightly scratch on the outlines of the chip.

[@screen-protector]

@@note2tee I was using this yes, they go off, but not 100%. Maybe it depends on the marker? But, this is how I've started and was helpful to me ;).

[@note2tee]

@@screen-protector mine stays when u apply flux, but as soon as the hot air blows it hot, it dissolve and gone without leaving any mark, the only way is lightly scratch a very short line on the solder mask

[@screen-protector]

@@note2tee Well, in this case this method is not always working though. I was using it and that's why I'm sharing :). But with scratching if there's no traces is not a bad idea as well :).

[@ferencszabo3504]

Nice job ! I used to work at the factory RMA and the BGA rework was always the tricky part. You've mentioned all main hazards of ripping up pads !👍👍

[@Mueller3D]

One step where it's easy to go wrong is when cleaning the solder with copper braid. It's important to cut off the piece of braid, or else the long braid will act as a heat sink and might cool down parts of it that aren't near the iron tip, possibly sticking to pads and ripping them off. Of course, you also can't cut the braid too short, or else it can disintegrate. A good method is to hold the piece of braid with soldering tweezers (for SMD rework), but most people don't have those. If you want to be really careful, you can use a piece of plain thin wire to wrap around the braid to attach it to the iron tip.

[@MadEDoctor]

Very accurate to the point.

[@SteveJones172pilot]

Good hint.. I was wondering why he used a small piece, and the thermal heatsink problem makes total sense..

[@cryangallegos]

I literally learned this yesterday lol I work in metal fabrication and absolutely know better regarding metallic structure heat sinks. Hoping to get a hot air station for my birthday so I can expand my capabilities.

[@SteveJones172pilot]

@@cryangallegos I got one for christmas and haven't tried it yet.. I have a small SMD practice kit I'm going to try first... and I hope I never have to work on a PI, but will be happy once I know I have the skill to do so if I need to!

[@dev-debug]

Wow, great comment. I'm going on 60 and have been using solder wick since the late 70s. Never stopped and thought about why it sometimes seems to need too much heat lol Learn something new everyday.

[@rouuuk]

Thank you for providing temperatures. For some reason channels never mention soldering temps.. its crazy

[@DannyWilliamH]

Cool. I know you're not a newbie to rework but some tips that a reader may see (and that may even help you): 1) Kapton Tape is awesome but it doesn't shield anything from heat. The tape itself is heat resistant, it doesn't block any heat so the board is still getting hit with whatever heat you're using. This still adds structural support to components so it's not useless! However, surface tension does that as well as long as you're not at 100% airflow. To remedy this and insulate the board components from heat, get some aluminum foil or aluminum tape that you then place over the Kapton Tape in the same pattern. Best of both worlds. 2) Once aligned on the board properly the chip will auto-align once molten. This is the best way to know it has in fact gone molten. Just watch it and then maybe a light tap after that but that's not always needed. The only time this isn't true is when misaligned or too much flux is used on the install. The adage of "never enough flux" is only wrong in one instance and that's IC installation. You want to coat the board pads with the thinnest film of flux you can. I'm talking a dab on the finger and then smearing it on the pads until it looks like there is hardly any on them. This is because with too much flux you can "float" the IC chip out of position and if partially molten it will cause you to have to do it all over again (remove, reball, prep board, etc). If it doesn't float it can be lifted off the board from boiling pressure using too much flux as well. All will seem fine and then the chip will just do a backflip from bubbling/boiling beneath it, haha. So use very little, just as much as you can make a very thin film with. 3) Use the right heat and nozzle. Ideally, you want the nozzle to fit the chip as exactly as you can. Chip bigger than your nozzle, use no nozzle. Go down from there when you get smaller ICs and you can then choose smaller nozzles as long as they're a good fit to the chip. 4) Finally, get a cheap kitchen griddle and use it as a preheater if you don't have a proper rework machine. They're less than the cost of a starter hot air machine (sub-$40) and use the exact same tech as a proper rework preheater. It makes work on smaller boards like this a breeze. You don't have to crank hot air if the entire board is sitting at, say, 150c before you do it. But good job and this is a good way to turn a cheaper Pi into a much more expensive model.

[@MadEDoctor]

Thank you! I have only one thing to add about the Kapton tape. It is true that it doesn't directly shield against heat like aluminum, but it can deflect the hot air flow from sensitive parts like plastic connectors. I actually have aluminum tape, but it isn't really meant for high temps, and when the hot air hits, its glue just disintegrates and it flies off to the other side of my bench...

[@DannyWilliamH]

@@MadEDoctor Both true and especially the lower grade aluminum tape (the easiest to find and what most of us have). Kapton Alone is 100% better than nothing and not useless (as noted). It's just not enough if working on larger boards as the heat needed will still melt plastics and such. Here on a Pi? Solid. I'm just referring to cases where temp control is paramount, think a lot of plastics on a thick board or the caps between GPU mosfets. In those cases you'll need more than Kapton.

[@quantuminfinity4260]

Thank you very much for taking the time to write such a detailed and well organized comment. Legitimately interesting and cool advice, I love hearing from people in industry willing to share what they have learned to others!

[@DannyWilliamH]

@@quantuminfinity4260 Thanks and I just hope it helps, be it in cool modifications like this or repair work. I'm not claiming to be the authority on it all but I have a lot of experience. I try to share small tips and hope it helps someone out there as we all start somewhere and it can be daunting at first. After seeing this I think I'll do this to my own Pi board. Never even considered it and that's funny given that I done similar so often on GPUs and other devices. Get a good deal on the RAM IC and this could save you a lot of money!

[@orbita1]

I've read this about kaptop tape and wondered, does the tape simply have a high melting point, yet still conducts heat. Or does it insulate heat, with the heat creeping from the exposed part of the pcb?

[@daemoncan2364]

Re: alignment. Can be made easier by making marks on the silk-screen that align to the corner pads on the board as well as similarly marking the corner solder balls on the edge of the chip with a spot (using a toothpick).

[@MadEDoctor]

I totally agree with that, but I didn't do this because I am actually selling the RPi's I upgrade, so I try to avoid leaving marks.

[@TheStuartstardust]

​@@MadEDoctor is this scalping or a help to the market? 🤔🤓😎

[@MadEDoctor]

@@TheStuartstardust I am selling them with minimal profit so I trying to help the market I guess...

[@jagohazzzard]

At our maker space, we've done a few of these. We made a ram chip alignment tool cut on our CNC machine that allows repeatable placing of the replaced ram chips. Out of 8 attempts, we had 2 failures. Also, the upgraded boards do not seem to perform as well as a native 8GB model in long term testing (transcoding video files using ffmpeg)

[@seanj1984]

Ram chip probably got too hot during the rework

[@marsovac]

to repeat the placing you just need to draw markings around the chip before desoldering, you don't need a cnc and chip alignment tools if not for mass operations, but you did not fail by overengineering, it is probably for other reasons

[@techromancer89]

I greatly appreciate that you explain not only what you are doing but the logic/reasoning behind doing it that way. You also sometimes go into other methods and why you selected this method over those. That is EXTREMELY nice, and very informative. Many channels do not go over things in this level of detail. I was disappointed you didnt show the balling process but thats no big deal. It just would have been really interesting to watch/learn about.

[@MadEDoctor]

Glad to hear you liked it! This is actually my first video ever published and I wanted to remove some parts that I thought were boring. But eventually thanks to comments like yours, I realized that If there were a bit more details about the soldering in general It would have been even better. Since the video was already published I had only one logical thing left to do. That was to try and create a tutorial dedicated to soldering/desoldering for different types of components including the BGA chip used in this video. I really don't wanna sound like almost every other creator who is promoting his own content and begging people to subscribe or like its videos, but if you are interested in seeing the re-balling process and other essential steps you can check out my other video.

[@robinpalmquist3679]

This is quite hardcore, you did an excellent job.

[@MadEDoctor]

Thank you!

[@la3135]

Awesome work!!! Amazing to see that this kind of upgrade is possible! thanks!

[@mattparker9726]

Thanks so much for this tutorial! I have been wondering about this for a long time!

[@AlwaysBolttheBird]

For a new channel. This is pretty much a perfect video. Please do more.

[@GreenStarbird]

Very cool, I didn’t think this was actually possible!

[@dsuess]

Just wanna say, you're my hero!! High-5 to you, great walk through

[@itssoaztek4592]

This is a very well made, very useful video for people who want to educate themselves. Thank you! Much appreciate this type of content even though I will not be in the position to try it myself.

[@Magicman8508]

Straight forward and nicely done!

[@Pitohuigrim]

Absolutely loved it. I would never try this myself but really informative.

[@BrianFain]

Great video. I will be trying this myself. Thanks for the info.

[@akasickform]

Beautifully and correctly done

[@hristiqndimitrov5249]

Great work very clean and well explained

[@redpillcommando]

You have mad hot air skills. I've never seen anyone free hand re-ball like that.

[@Sydney268]

That wasn't a free hand reball, he was just cleaning the pads.

[@redpillcommando]

@@Sydney268 Yep. I picked up on that later in the video but decided to leave the complement anyway because it looked like he could have done it by hand if he wanted to.

[@torak456]

Very much so looking forward to more videos.

[@denismilic1878]

Very good no BS video with all pieces of information. I hate computer voice videos but not this one. Very, very, very good. I rarely subscribe but I'm proudly subscriber #9. If you are able to speak English even badly with strong accent I think that will make the video even better.

[@MadEDoctor]

Thank you! I will consider buying a streamer mic or smth in the near future, so I could at least try doing the voiceover myself.

[@apo_ka]

you just blow my mind! Amazing video!

[@marcelpi0]

Very nice recording style. Hope there will be more content in the future.

[@matthewhudson2702]

Dude your cooler then lemonade on a hot summers day!! Great vid gonna attempt on my raspberry pi 2 and 3

[@m.projects]

I love seeing microsoldering & BGA rework videos and I want to do that kind of work some day, I've already worked at a phone shop with the tools needed and got some practice by removing CPUs from phone/tablet boards (those Intel Atoms look pretty nice you know :P)

[@thomasj4370]

Thanks for the clarification that I'll not be able to do this. You got yourself some decent skillsets-manual and educational-presented in an enjoyable unspectacular matter which forms to a pretty impressive tutorial tailored on the advanced solderers among us yet still entertaining all others into SBCs. Sorry for the overwhelming long sentences I’m leaving behind me whereas indeed I simply could written: “Very nice clip! I like it!”

[@vladislavkaras491]

Really cool stuff. Thanks!

[@kichicattv]

i've been searching rapsberry since last year prices are skyrocket for 4gb to 8gb but thanks to this tutorial something I learn

[@GoutamDAS-ls1wb]

Very good presentation! I wish I had the experience to do this flawlessly. I am sure you have been doing this a lot with other SMD's. I wish the RPI foundation used an IC socket for the memory--especially if no change to the firmware/OS is necessary. This upgrade would be great on the RPI5 scheduled to be released next year maybe.

[@_DSch]

That would be really expensive and probably cause reliability issues too (as well as being unneccesary on an embedded device)

[@Bianchi77]

Nice info, thank you for sharing it :)

[@izac_7991]

I don't even have a raspberry pi but I really enjoyed the video. Looking forward to see what comes next.

[@DominicClifton]

I do this the same, except for 2 things: 1) add flux under the middle of the chip on the board, place the new chip on the flux. 2) after removing the old solder I apply fresh leaded solder to all the pads using a molten solder blob on the end of the iron. Why? 1) When the balls on the bottom of the chip have flux on the the thermal transfer is better. 2) Fresh leaded solder under the balls also then gives you about the same amount of solder under each ball that you'd have normally as when the boards are made they use a stencil with openings for each pad and apply solder paste to apply paste to each pad. this solder paste melts and combines with the solder on the balls on the bottom of the chip. Works for me, i design, build and manufacture PCBs using TFBGA100 packages and have replaced a few BGA chips for my customers with success every time.

[@anomicxtreme]

No need to apologize for something you got took for yourself, glad you caught it before installing it.

[@EasleyDone.]

excellent narration

[@Theilencer]

Great video! Might try this. One tip if you do lots of hot air soldering. Try to find a vacuum picker with heat shrouds and spring loaded pickers. That way you minimise the risk of overheating or damage to the board.

[@MadEDoctor]

Thank you! Actually very nice suggestion.

[@seanj1984]

I enjoy the video good information thank you for finding the compatible memory so I did not have to. Much appreciated.

[@joels7605]

Spectacular work, good sir. Hopefully someday you can get your hands on a 16GB chip for another test. Keep up the good work.

[@MadEDoctor]

I hope so too :)

[@akhilgeorge5634]

You are great brother nice video 🤠

[@multiomer1997]

Raspberry Pi Foundation has left the chat.

[@wastedangelematis]

Kudos , tips fedora to the legend

[@nevilenobody606]

He makes it look easy but the reality is that BGA chips are extremely hard to solder without a lot of practice.

[@rpsmith]

Great Video! Thanks! 🇺🇸

[@mkosmo]

The 2GB memtest issue is likely because you're running 32-bit Raspbian.

[@rallisf1]

An x-ray reflow station makes this a lot easier. I used to work at a repair shop and we mainly did reballing of failed playstations, xbox and laptops. We fixed a few GPUs as well but mostly with bad ram chips, which is the same procedure as you show here.

[@superslimanoniem4712]

Xray reflow? Like a fluoro for computers?! That's insanely cool!

[@vanhoteen]

thanks for telling the temperatures and flows

[@JrManPT]

Great content!

[@jimbotron70]

Very clever, I wish I could be able to do that on my Pi 3.

[@TheSlyMouse]

Awesome video! Even the part where you were going to upgrade it even more but realized the chip would have been a scam. If you do make another video where you succeeded to get the chip include that as part of the story, I think it would be very interesting

[@forsaken1776]

I've thought of this idea but had no way to get it done or the know how. NICE VID

[@Epic_tech]

Man it was a great tutorial

[@awesomedee5421]

You are cool. I loved the video. Providing all the step by step details to do it myself. Thanks for providing links to all the parts needed. Looks like it's christmas for me again. The board holder looks soo useful.

[@MadEDoctor]

Yeah the board holder is really good. It might seem like a lot of money for a block of metal with some springs, but it’s worth it.

[@AdmV0rl0n]

Love your work, nice stuff. An yea, 16GB on a pi would be interesting!

[@Lunolux]

no your are awesome, thank for showing something that i will never do, this is insane

[@scientificidiot4165]

amazing work! instant sub

[@RunTheTape]

you can mark the corners with a sharpie on the original memory chip before soldering, it makes life a lot easier to match the position with the new chip.

[@MadEDoctor]

Yes you can, but the isopropyl alcohol used for cleaning the burnt flux will clean the sharpie too.

[@RunTheTape]

@@MadEDoctor sharpie knife then :)

[@TheBython]

I hope you will post more awesome videos about single board computers. I`m waiting

[@scottwilliams895]

Impressive skills!

[@Kmnri]

Ill be honest i clicked the vid fully expecting it to be some clickbait garbo, I did not expect that :) thumbs up. Altho you can simply get alternative SBC, rbpi isn't the only one with good support anymore. Like orange pi

[@Ferferite]

amazing job, sadly my pi3 B gave up some time ago with no signs of life apart from a red light. the pi shortage is real

[@williambritcliffe2211]

Excellent video

[@MadEDoctor]

Glad you liked it

[@juanman2874]

You are awesome!

[@AzazehlWhinchester]

Very cool!

[@djdawless]

Good video nice to know it can be upgraded... Luckily I already have a 8gig Pi that I bought when they were cheaper, hopefully the price comes back down soon, my eyesight and steady hand isn't what it used to be so I doubt I could do this upgrade, I don't even know where my soldering gear is, it's been so long since I used it :D all the best.

[@meddiys6171]

Excellent.

[@mattthomas3467]

Excellent video!!

[@MCgranat999]

This video is basically a middle finger to all the "smartass" users on all the forums that tried to ensure me that this is impossible. Thank you!

[@MadEDoctor]

Actully I was wordering for almost 2 years now if this its possible and now came the moment of truth for me and I guess for the most of you 😅

[@MCgranat999]

@@MadEDoctor Absolutely! Recently I've purchased my pi 4 with 2GB of RAM with the intention of upgrading it when the memory chip gets just a little bit cheaper. Until now I only guessed that it should be possible but now I can be absolutely sure it works!

[@PerspectiveBeyond]

I'm curious if this type of upgrade is possible with a RPi 3, because Model A and B had 512 MB and 1 GB respectively. It would be awesome if these could be upgraded to a higher capacity as it would give them much more usability. Either way, great video :)

[@MadEDoctor]

I think it is possible. I will consider doing a video on RPi 3 in the future.

[@ninline2000]

​@MadEDoctor I'd love to see that.

[@twilmer34]

It's not possible to have more than 1GB on RPi3 as the VideoCore is driving the RAM and there are internally not enough address bits.

[@Joromonni]

even the 3B+?

[@unfunf22]

@@Joromonni i have one 3B+ yes it would interesting to know if it is possible with 3b+.

[@yurigansmith]

Ja wie geil ist das denn!

[@icanc0]

does this work on older revisions of the pi 4? not sure which revision you are using but those don’t have an 8gb variant with the same board.

[@------country-boy-------]

Always wanted to know if this was possible. Thankyou'!!!

[@wcg981dddwwwhhh]

I tried and it worked. it's very diffcult for the first time to do the chip remove and resoilder.

[@ericbwertz]

terrifying -- hope to see this in the Horror category at the Oscars this year.

[@chrislambe400]

The most amazing part was getting the computer voice to say sodder

[@MadEDoctor]

True😅

[@mjulev]

Браво !

[@shatteredprism]

I'm very new to soldering and was wondering if it's flux and a solder wick to clean up the solder to remove the old ram? /genq Edit: I'm watching this without audio because my headphones are currently charging, so I may delete this if I remember to watch it later with sound.

[@djstraussp]

This is terrific 💯. Now, it's time to unlock the ability to upgrade to a 16Gb Chip 😁

[@MadEDoctor]

🤔

[@AhmedRamadan-vv1oe]

no u r awesome, thx

[@rachidtessoudali9337]

Awesome

[@TechwithStefan]

super nice :)

[@lets-learn-tech]

Nice and neat

[@-ColorMehJewish-]

Dude, that is amazing. I'd want to practice on a spare board before I go testing on ones that are gouged as much as RPi 4's are. (idea for another poss video --- if you could find a cheap practice project for newer soldier'ers to try out, before moving to the real thing) Thanks for the video, idea and for showing your skill. I am a much better visual learner.

[@JeffGeerling]

"Nowadays this is the cheapest way to get an 8 GB Raspberry Pi 4" 😢

[@craigpowell4142]

I've been interested in trying hot air rework and now I have a goal, as I have two 1GB RPi4s that could make use of this. But of course first my plan will be to take boards from old equipment that doesn't matter and practice, practice, practice. Well put together video! The artificial voice was a little annoying but I can fully understand why you've used it. If you haven't added it since the last time I checked the description, can you provide the info on your fume extractor as well?

[@MadEDoctor]

Thank you! I just added the link to the fume extractor in the description :)

[@SchoolforHackers]

149 subscribers?!? Oh dude this channel should explode. Sub.

[@MadEDoctor]

I am actually looking at the analytics and I just can't believe what is happening to me and my channel 🤯 And I am so thankful ♥ You all are so amazing!

[@jorggamingcr409]

Quick question, I may have missed it, but how did you know the correct orientation of the ram chip so every pin on the memory is connected to the respective one on the PI? I would guess the ram had a datasheet and probably (I havent serch that deep yet) that the documentation of the PI has a pin specific documentation as well?

[@MadEDoctor]

Well every chip has a marking on it for the orientation. Usually a dot or indentation.

[@sharp7171]

Dude you are siiick. Where did you start learning how to solder? Just practice I guess? Any suggestions?

[@MadEDoctor]

I need to be completely honest I learned like 80% from KZbin and the other 20% just came with practice and experience. You can check out Louis Rossman and NorthBridgeFix for great soldering tips.

[@sciencoking]

Interesting that the ram auto-detects. Makes me wanna try it with a Pi 2 or 3.

[@silitekmodder5681]

Is it possible to upgrade the RAM on an original Raspberry Pi? It would be a bit tricky since the RAM is soldered to the top of the processor

[@SeanHoulihane]

I remember when we sent BGA boards out to assembly houses who had X-ray machines. Now people are following video tutorials to do it at home....

[@user-xm1ts5dt9v]

Such a nice video. I don’t have any experience of soldering the memory. So the form factor and pin layout is same for that size memory?

[@MadEDoctor]

Yes it is the same. Because we use the same type of memory in the same exact physical package.

[@user-xm1ts5dt9v]

@@MadEDoctor Thx for the reply! Look forward to see ur next videos~

[@granudo]

Which ai tool do you use for your voice overs?

[@TareqAstroPhoton]

So i have to buy all those or most of those and learn this and that only to upgrade from this RAM to this RAM when i can save and buy that upgraded RAM from beginning??!!!

[@fredrikrutgersson]

Nice. I have done Memory Upgrade on Atari ST from 512Mb to 1024mb and later build own sim card so you can easy upgrade to 4Mb.

[@robclaridge6236]

Just a small thing. Could you say the temperature you are using whether it is Celsius or Fahrenheit in your videos please. I don't mind doing the conversions myself (if at all required), but would be very handy to know which system you are using to avoid confusion. Would be so much appreciated. Fantastic video. Subscribed.

[@MadEDoctor]

Yeah I just realized that I missed to mention this… I am using Celsius since I am from Bulgaria.

[@jameslee3663]

I believe he said 400 degrees, this is fahrenheit

[@dingsens2810]

@@jameslee3663 400°F is around 200°C, this wouldnt get the solder even slightly molten... We are talking about 400°C of cause.

[@gg-gn3re]

I've soldered and done pcb stuff for ~20 years but you really need surgeon hands to do SMD stuff like this

[@sherp3000]

So we've seen ram being upgraded, thanks for that. But by any chance do you have a compute module 4 without wifi and want to upgrade that to have wifi? Am looking into this since it was the only raspberry pi i could get my hands on.

[@MadEDoctor]

I don't have a compute module currently, but I will consider this as a project idea.

[@codelinx]

This is awesome, I would love to upgrade some rpi 4 I have, but finding the right ram that's high quality may be a problem.

[@MadEDoctor]

There isn’t a much choice you have when it comes to memory😅 It’s not easy and economical to make fake RAM, and so there are like 4-5 manufacturers worldwide and thats it. It’s not like buying a fake lego just to find out that there are missing parts. The thing is that you need to be ok with getting a second hand RAM installed since nobody can guarantee if it is new or second hand when purchasing from sites like Aliexpress. Also except for a very small percentage where the chip has a manufacturing defect, the RAM easily outlives the service life of all the other components not only in the Pi world, but also in Laptops and Desktop computers.