Hi Self Hosting Lemmings!
I’m looking to upgrade the RAM in my 3-node proxmox cluster and could use some advice. I have 3 HP ProDesk 600 G3 Mini PCs that claim to support up to 32GB of RAM. However, I would really like to upgrade to 2x32GB for 64GB total.
Is it possible to run with more RAM than the recommended amount? If so, are there any problems I might run into? Any insight is greatly appreciated, thanks!
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There are a few things that determine the amount of RAM your PC can handle.
Simplest is the amount of slots on the Mobo. It’s hard to put extra RAM into a machine if there is nowhere to plug it in.
Next is the motherboard limitation. This is mostly based on the type of RAM it takes. DDR4 has a maximum size of 64GB per DIMM and DDR5 maxes out at 512GB per DIMM
Finally and most crucially is the CPU. CPUs have onboard memory controllers these days and they can only handle the amount of RAM that they can address. This value changes from CPU to CPU so you’ll want to check the specs for the model you have.
If you go over the supported amount, the PC will likely just fail to POST and never boot. If it does boot it will just ignore the extra RAM and never actually use it.
This is good comprehensive advice that allowed me to do more of my own fact checking against my hardware. Looks like my hardware should support 64GB RAM just fine, with the caveat that my CPU will only be able to run the RAM at max of 2400Mhz. But I’m ok with the speed limitation, since I’m after the capacity. Cheers!
It doesn’t say recommended, it says maximum.
It might work if you put more in, but there are a number of components that would need to support it.
If the machine supports up to 32GB RAM, it probably only has the hardware for 32GB RAM. Maybe it only has 25 address lines for RAM.
It may or may not work, unfortunately.
I successfully ran 2x32GB in a Dell XPS 15 that “didn’t support” it, because the larger DIMMs didn’t exist at the time it was designed and documentation was done up.
It’s not going to hurt to try, but if you have two DIMM slots it’s worth a shot; the slots are already wired up to address lines! Maybe try with one first?
Edit: the CPU specs say that it supports 64GB and only up to two memory channels. It’s looking pretty good on that end.
I would get one 2x32 kit somewhere you can return it (or even 1x32 if you are worried) and try it out, sometimes it does work but sometimes it won’t POST. Like the other person said, it might work but there really isn’t a way to know for sure other than that. I have run into situations with systems like that where that was just the largest available at release date for them to test and validate and larger DIMMs work fine so it’s probably worth testing in my opinion.
I am curious myself, let me know if you do test it, those look like cool machines for small clusters.
Try it and see what happens. Often the maximum on prebuilts isn’t the maximum that the hardware will support. My last laptop claimed 32gb maximum ram but works fine with 8+32gb. Just be aware that it might not work and have an option to return or sell the ram on if it doesn’t.
Edit: frequently on older hardware the memory controller can’t address more than a stated maximum amount of memory. This hasn’t really been an issue for a while, but like others mentioned you might not be able to see or use memory beyond that limit. Or the machine will just fail to POST. Always test unsupported memory configurations overnight (at least) with something like memtest86 before trusting them with any important data.
Word of caution: I added more than max ram to a Synology server once and it “checked out” but Plex sent garbled transcoded if it were ever used. I feared data corruption on routine data checks so I swapped it back.
That was long ago and doubt newer models have the same limits, but it made me think of the data vs risk factor.
Yeah, fair point. I’d throw an overnight memtest86 load on it before trusting it for anything important. You should always do that with new memory, especially if you’re trying to do something unsupported.
If it works at all, you shouldn’t have any other issues. For example, Intel NUCs have a stated maximum amount of memory, but there are plenty of online discussions about running higher amounts without issue.
i found a couple vendors implying 2x32gb compatibility, one selling a 2x32gb ram kit (‘guaranteed compatible’ they say) and the other selling the pc itself (oos, though) with 64gb, for this model even though its published specs say 2x16gb max. so it might just be possible, depending on the specs of the memory modules.
buy one kit first from a vendor with a reasonable return policy and try. that’s all you can really do.
