2 kits of CMD4GX3M2A1600C9 won't work at XMP settings

Hi All,

Been having a few problems with my CMD4GX3M2A1600C9 kits. I have two so four sticks of 2gb. I have previously installed them in my old system - Asus P7Q57-M DO with an intel core i5-650 cpu (everything else the same as now) but they seemed incompatible with the motherboard (or so I thought):

At the XMP settings of 9-9-9-24-2t @ 1.65V:

• When both kits were in, memtest would fail on test 6 usually, but producing only a few errors (5-10) in an overnight run.
  
• One of the kits, when installed on its own, would fail memtest miserably (100+) errors over 12 hours
  
• The other kit would pass 12 hours of memtest without any problems BUT when I left in the system I would get strange 'breaks' in the audio and a BSOD every so often.
  

I didn't really test the RAM at lower settings (if it says 1600 on the tin, surely it should run at 1600). I sent the (what I thought was) faulty kit from above back for an RMA with scan. They didn't find any problems, charged me £25 to get it sent back. I thought OK, must be compatibility problems with my board. I ended up going back to my 2 x CM3X2048-1333C9DHX kit and the system ran fine for a few months.

Now, I got a new mobo and cpu last week (as per specs). And I'm facing the same nightmare:

• All 4 sticks are in at the XMP settings.
  
• Tested with memtest AND windows memory diagnostics and no problems.
  
• BUT windows isn't stable - BSODs within the first four hours or so after boot. All the BSODs have something to do with kernel corruption. I've checked the event logs, and some of them mention something about an incorrect bit in the kernel.
  
• Can't get through an overnight test of prime95.
  
• I've tried reinstalling windows, reset the bios, updated the bios, and no joy.
  

Eventually I decided to use all auto setting for the memory - 9-9-9-24-2T 1333 @ 1.5V. It's been running prime95 in windows for the last 16 hours. No problems.

Any ideas what can be wrong and why my ram seems to be unstable at 1600 but fine on 1333? And why doesn't memtest detect anything (at least on this board) but windows isn't stable?

Sorry it's a bit long. Any help would be greatly appreciated.

Antony

PS. I am aware of the P67 sata issues, and am running off the two ports that are not affected.

my ram seems to be unstable at 1600 but fine on 1333?

it could be that only a SINGLE kit was designed to run at 1600, not 2 kits.

that kind of mixing usually requires lowering the speed so both kits can play nice together.

there are thousands of threads like yours here and only a small handful have been successful at running multiple kits at XMP settings. sometimes you have to compromise speed for capacity when your ram did not all come from one single kit.

Synthohol - the article in your sig was quite useful.

I saw in the asus bios manual that apparently intel does not recommend voltages of 1.65 and above. So I set the voltage to 1.645 in the bios and the system has just finished its tenth hour of prime95 without a hiccup with the memory running at 1600!!!

Maybe the higher voltage recommended by corsair is what caused the instability in the memory controller in the first place? Perhaps this is an issue that needs addressing?

Thanks for your help. I will post again if any problems develop in the next couple of weeks.

Thought I'd post an update.

Memory was working fine with the above settings for two days, then it decided to shell out a barrage of BSODs, starting with a couple of of 0xC2, followed by a whole lot of 0xA1 Memory_Management ones.

I though it was the system overclock, so I went back to stock setting for everything, including the ram running at 1333mhz. Still the 0xA1 BSODs. I tried increasing the VCCIO a bit, and also played with the dram voltages. No joy, still BSODs, some within one or two minutes of booting into windows.

Ran it through memtest with my fingers crossed that it will show some errors so I can finally get it RMAed, but no errors throughout the overnight run. sad times.

Got fed up, stuck my old 2 x CM3X2048-1333C9DHX kit in. Went back to the previous overclock. Stress tested. Memtested. And it's been running fine for a week now. No BSODs in sight.

Memory controller can't handle 8gb? or crap memory? And the bigger question - What can I do?

I'm now stuck with the two sets of memory, that seem to be incompatible, or defective, or I don't know what, that cost me a fortune and I can't seem to do anything with. I can't return them as they're near half year old. I can't sell them as i would hate to do this to anyone else. AND I cannot be bothered to waste any more time figuring out what's wrong as when the memory is not in my builds, everything seems to work fine.

Any suggestions?

I'm now stuck with the two sets of memory, that seem to be incompatible...

thats correct. there is no expectation of mixing sticks from 2 or more packages and having them play nice in the sandbox.

a single 8 gig kit will be supported though.