Mixed Corsair DIMMs and A8N-SLI Deluxe

[El-Sama]

I just received some CMX256A 3200PT ram in a TWINX package for a total of 512MB, to add to my existing 512MB of ram, also from Corsair, some CMX256A 3200C2PT.

 

My board will post and run, but it's not detecting all of the ram. Only 512MB is ever detected.

 

I can take out the old stuff, and the new stuff detects just fine. And obviously, the old stuff works great.

 

Is there some issue with these sticks working together? I tried increasing the vDimm to 2.9, and setting REALLY loose timings, and even raising the vCore on my 3000+, just in case. I have a 520w Vantec power supply. The BIOS is currently 1003, but I tried the 1004.001 beta to no avail.

 

So do I need to return this stuff and get C2PT to match my older stuff? That would be kinda silly, I would think, since I can force the CAS to be 3, and it doesn't make a difference.

 

TIA

[Wired]

It's not recommended to mix modules of different part #s.

[El-Sama]

It's not recommended to mix modules of different part #s.

 

Okay, that being the case, is there a specific reason why they don't work?

 

I don't mean to be picky, but I thought the days of "this DIMM doesn't work with this thing" were behind us. That's what standards bodies like JEDEC are about, right?

[RAM GUY]

Well yes and no. For any MB to run dual channel the modules would need to be identical. In this case they would need to be the same part# and revision.

I believe I have seen the same type of suggestion in most MB manuals, but it is usually subtle.

 

JEDEC, just defines a spec. for a speed grade, they would not be able to guarantee 2 modules would run together in the same MB.