Will 1866Mhz DDR3 work on an older mobo?

[probedb]

I'm slowly updating 2 machines and I want to move my current desktop memory into the server.

I was planning to buy some Corsair 1866MHz DDR3 (2x8GB) but my mobo (Asus P8P67 Pro not rev 3.1) doesn't explicitly say it supports it.

Will the faster RAM just run more slowly?

The desktop will get updated eventually but I don't see any point buying new RAM for my server (it's an old DDR2 mobo) when I can transfer the stuff currently in my desktop.

Cheers,
Paul.

[kalniel]

It should work, check that the voltages of the RAM are supported by the motherboard and your CPU. Whether you run it at 1866 or a different speed also depends on your CPU.

The explicit support (via QVL?) is more a collection of modules that have been tested and will be guaranteed to work, but once they make newer motherboards they don't usually bother continuing to test newer RAM on older motherboards.

Also check for bios updates as high density modules might need some supporting tweaks.

[probedb]

Thanks for the reply. That's what I figured. BIOS is the latest they've done so I'll give it a try

[Bonebreaker777]

Exactly as kaniel says, but I can't forsee voltages required by modern DDR3 memory modules unsupported by old motherboards.

Just make sure that you have the newest BIOS and go. If your mobo supports XMP, just enable it (choose the best based on your equipment), that should ensure additional compatibility.

[probedb]

Exactly as kaniel says, but I can't forsee voltages required by modern DDR3 memory modules unsupported by old motherboards.

Just make sure that you have the newest BIOS and go. If your mobo supports XMP, just enable it (choose the best based on your equipment), that should ensure additional compatibility.

Even with the DDR-1333 I currently have, enabling XMP causes my mobo to fail to boot sometimes so I just set it to Auto.

[kalniel]

I don't recommend XMP. It doesn't take any account of different motherboards or CPU memory controllers, it just says 'this ram would like x volts for y timings' above and beyond jedec specifications (ie can request voltage out of range or a wider selection of timings and speeds). If you know your motherboard/CPU can do it, but you don't want to make the changes yourself, it can be great to quickly set your RAM to it's advertised speeds. But if your board/CPU isn't happy then XMP can be a bad thing - I have some 2000mhz rated RAM but my memory controller/cpu clock can't run anything close to that speed, so enabling XMP would just cause boot failure.

By the same token, be careful with Auto settings - if they try and run higher speeds then they can tend to jack up the voltages to make things stable out of the box. At the least I would set the speed and voltage manually, and see what settings it's picked for the timings. If they look out of whack then specify the main timings manually as well.

[Agent]

The new RAM / old mobo scenario shouldn't ever be an issue due to the JEDEC specifications. All DDR3 RAM should adherer to the standard voltage and frequency specifications that have been set. Anything above it is nice, but to be sold as DDR3 it absolutely must have the default JEDEC table support or the ability to run at them.

[kalniel]

The new RAM / old mobo scenario shouldn't ever be an issue due to the JEDEC specifications. All DDR3 RAM should adherer to the standard voltage and frequency specifications that have been set. Anything above it is nice, but to be sold as DDR3 it absolutely must have the default JEDEC table support or the ability to run at them.

Should, but we know that high density chips sometimes cause issues, and some memory controllers are more stable if they aren't operating too far from the RAM voltage, so if the RAM is so new that it requires very little voltage the memory controller might be more unstable.

[Agent]

so if the RAM is so new that it requires very little voltage the memory controller might be more unstable.

Interesting - DDR3L has to be aware, and support 1.5V if it encounters it, so I'm unsure on why this should be an issue.

If this was a new motherboard and old RAM, then I could see the issue. Bay Trail and Some Haswell systems I know get very upset with 1.5V RAM, but I'm not sure where the issue could be the other way around?

If you manually go and lower the RAM voltage from 1.5V to a lower amount (say 1.35V) on such a system, then I could potentially see an issue, but otherwise it should just act like any other stick of RAM.

[kalniel]

Interesting - DDR3L has to be aware, and support 1.5V if it encounters it

Right, but a motherboard looking up the spd table might set said RAM at 1.35v and if the memory controller was designed and is happiest for RAM at 1.65v it might be unstable without intervention.

[probedb]

Thanks again folks. It's on my list for March

[Agent]

Right, but a motherboard looking up the spd table might set said RAM at 1.35v and if the memory controller was designed and is happiest for RAM at 1.65v it might be unstable without intervention.

The OP's mobo is a Asus P8P67 Pro, so 1155 / Sandy & Ivy Bridge, neither of which have a MC that runs at 1.65v, so surely it shouldn't be an issue regardless?

I've done a bit of Googling (because I've not actually come across this issue) and I can see a few places saying that the RAM / MC voltage should be within 0.5V of each other. Fair enough if this is the general consensus - I can understand why that might be an issue for other systems

I'd image a pretty rare situation though!

[nniitt]

The OP's mobo is a Asus P8P67 Pro, so 1155 / Sandy & Ivy Bridge, neither of which have a MC that runs at 1.65v, so surely it shouldn't be an issue regardless?

I've done a bit of Googling (because I've not actually come across this issue) and I can see a few places saying that the RAM / MC voltage should be within 0.5V of each other. Fair enough if this is the general consensus - I can understand why that might be an issue for other systems

I'd image a pretty rare situation though!

RAM at 1.65V, not IMC at 1.65V. And there is no definite relation between RAM voltage and IMC voltage!