Asus P5Q3 with 4xCMX4GX3M1A1333C9 - unstable

I've been trying for 5 days to stabilize this system, and desperately seeking any help I can get.

I used to have 4x2GB (total of 8GB of DDR-3) running just fine with a 20% overclock on the CPU and the ram fixed to 1333Mhz

I wanted to upgrade to 16GB of ram so opted to get 4 of the CMX4GX3M1A1333C9 (which the configurator says should work) modules (unfortunately trading away my old ram to be able to afford this) Now I'm in dire straights - here is what I have tried (thanks largely to advice here on this forum (at least I can boot and stay running for more then 5 mins):

I have removed the CPU OC running with the FSB at 333MHz and PCIE 100Mhz fixed. I have the ram Underclocked to 1066 and at these settings I can get through 4 hours of memtest and see no problems with Prime 95 (which is running right now actually) This after constant BSODs if I tried to keep the ram at 1333Mhz. I could get through memtest fine with the ram underclocked and the CPU OCed back to 400Mhz FSB though - but... in any of these configurations...

If I start up anything intensive like Photoshop or a game my system either hangs or BSODs almost instantly. I also tried increasing Northbridge and/or Ram voltages (tried up to 1.28 and 1.7 respectively) but if anything that seemed to make things worse.

Could this be something related to the GPU/RAM Interaction (seems to be a direct trigger that accessing the GPU will kill the system with this current config)? I have no idea what to try next - any suggestions would be much appreciated!

Using four individual memory modules rated for 1333 MHz. is more than likely the problem instead of purchasing ONE tested, matched kit of 16 MB. rated at 1333 MHz. At best TWO of those DIMMs might run at 1333 MHz. but four is highly unlikely.

Read the Memory Upgrade Resource Guide info. at the link below for details:

http://forum.corsair.com/forums/showthread.php?t=87341

I read that guide, although this concept of a kit being any different then the individual modules is a new one (It's moot because there were no 16GB kits available from the suppliers I could find - was the 12GB a typo?) - Right now I'm only trying to get them to run at 1066MMhz

I guess I'm just not sure what to do now - I have already returned 8 Modules trying other brands I was beginning to contemplate changing to a different motherboard - any thoughts?

Unless you buy one 16 GB. kit of tested, matched RAM there's little likelihood of success.

There is no new concept in the Memory Guide. The only means to know if multiple DIMMs will function together properly at a given frequency and latencies on a particular platform, i.e. Intel/AMD, is by actually testing them. That is why Corsair tests 100% of the RAM and speed/platform grades the memory accordingly so you can purchase a proper tested, matched kit.

Changing mobos isn't likely to resolve the issue. If you actually need/desire 16 GB. of RAM then you need to purchase a 16 GB. tested, matched kit for your CPU.

Yes the 12 GB. was a typo which I corrected. :>(

ok well... guess I'm stuck then... can't see a 16Gb kit offered anywhere online and what I have won't work. Just a side note - I couldn't see anywhere in that guide where this, seemingly rather critical point, is mentioned, they only caution against mixing and matching different types of modules (which I have always known not to do) - but live and learn I guess...

I was able to remove 2 modules and have it running again back at only 8Gb 1333Mhz with the CPU OC back in place - sadly now with this slower 9CL ram as opposed to my 4 sticks of 6CL from before - so much for my "upgrade" :(

I do appreciate the info - I'm just grumbling to myself, not at nor about you (don't want that to come across the wrong way)

It does leave one to ponder why individual dimms remain the most common thing available though - if you both can't rely on them to work in a group and when all modern mobos are at least dual channel and you can't mix memory. I'm surprised memory selectors don't have huge bold flashing lights warning people against ever buying anything but a kit - I have actually never bought a kit of memory before in my life, despite having built close to 70 PCs and I've never had a problem with using groups of individual DIMMs. Again, not disputing what is obviously accurate information, just kinda shocked to learn it now after all this time and surprised it's not far more visible in forums and in places where I would expect to find this highlighted.