Corsair XMS3 DDR3 1600MHz not stable above 1200mhz...

[years]

Heyhey. The problem is as the title states. The sticks are supposed to be set to 1600mhz, 1.65 dram voltage, 1.20 QPI Voltage, CL 9-9-9-24, and I did just that but they just won't act stable at all. I've had to set them down to 1200mhz to get my system stable. I tried upping voltage, loosening timings (not really an option as they are supposed to work with stock timings), underclocking my cpu...

Anyone with an answer out there? I've been trying for so long, and I've had so many problems with ram before, so im really tired of it. My first build (asus p5q pro, q9550) had one defect ram slot, my current build I bought with 2000mhz 6gb sticks, where one won't work on cold boots, then I bought these sticks to use while I send the old ones for repair, and they won't run at their supposed speed.

Current build:
Asus p6t SE
Intel Core i7-930 @ 4Ghz
ATI HD5870 crossfire
Corsair XMS3 DDR3 1600MHz (http://www.komplett.no/k/ki.aspx?sku=492643) link for the ram sticks.
APX 1000W PSU

I'd really appreciate your help if you have any input!

[Zyzzyx]

Those particular sticks seem pretty fickle, they're hit or miss in regards to running at the max speeds. If you can't set the profile after making sure the bios is updated, you may be out of luck. It probably isn't worth risking your CPU over a slight speed increase, if you aren't able to get it stable.

[Nejji]

Heyhey. The problem is as the title states. The sticks are supposed to be set to 1600mhz, 1.65 dram voltage, 1.20 QPI Voltage, CL 9-9-9-24, and I did just that but they just won't act stable at all. I've had to set them down to 1200mhz to get my system stable. I tried upping voltage, loosening timings (not really an option as they are supposed to work with stock timings), underclocking my cpu...

Anyone with an answer out there? I've been trying for so long, and I've had so many problems with ram before, so im really tired of it. My first build (asus p5q pro, q9550) had one defect ram slot, my current build I bought with 2000mhz 6gb sticks, where one won't work on cold boots, then I bought these sticks to use while I send the old ones for repair, and they won't run at their supposed speed.

Current build:
Asus p6t SE
Intel Core i7-930 @ 4Ghz
ATI HD5870 crossfire
Corsair XMS3 DDR3 1600MHz (http://www.komplett.no/k/ki.aspx?sku=492643) link for the ram sticks.
APX 1000W PSU

I'd really appreciate your help if you have any input!

I'd bank on your overclock causing the problem here. The QPI voltage specified is meant for a system at stock clocks, however to get your processor up to 4 GHz you must increase your Base Clock significantly. Not only does this increase the CPU speed, it also increases the data rate of the QPI data link itself, which requires more power. RAM speeds do affect the voltage necessary for QPI, however if you want to run your RAM at its rated speed along with the processor overclocked you will need to bump up QPI voltage. Try with a QPI voltage between 1.25 and 1.3 volts and see if that remedies your problem.

Edit: It's also good to know that going over 1.65 volts for the RAM itself can be very bad on Intel's processors.

[years]

I already did up the qpi up to a max of 1.40 which was recommended by various google hits. I guess the sticks are just that bad then.... Thanks for the answers anyway!

[Cilraaz]

Try dropping your command rate to 2T, if you haven't already. With my G.Skill 1600MHz CL9 RAM, I had to do this to achieve stability. Also, make sure your QPI multiplier is set to the lower of the two values.

[years]

I havent seen anything called QPI multiplier? What does it do?

[Cilraaz]

I havent seen anything called QPI multiplier? What does it do?

Just as the CPU and RAM multiplier help determine the speed of the CPU and RAM, the QPI modifier helps determine the speed of the QPI link. When a Core i CPU is overclocked, if the QPI modifier is left high, it can create instability if the BCLK is too high.

[edit: Checking specifics on your motherboard model, it looks like people are saying to set the UCLK to 2x RAM speed (3200MHz in your case) and make sure the QPI frequency is set to its lowest value, which should be 18x.]

[years]

I cannot seem to find QPI frequency in my BIOS. The only thing i can find is QPI Link transfer Rate or something, that I set to the lowest, hoping that was what you meant. Any idea where I can find QPI Frequency? I can chose between 7k GT/s, 8k GT/s or 9k GT/s or something like that

[Cilraaz]

QPI Frequency/Multiplier times BCLK gives you your QPI Link Speed. If you put it down to 7k, you should be good (might have been 7200 or 7.2k?).

[years]

it was something around 7k yeah. Couldn't get past windows loading with 1,45 QPI voltage, 1600mhz ram, 20 CPU multiplier, 7200GT/s QPI link speed, 200 BLCK, 1.7 DRAM voltage

I still cannot find the QPI Multiplier/Frequency... Any idea why I cant find it? It just doesn't show in bios

[Cilraaz]

it was something around 7k yeah. Couldn't get past windows loading with 1,45 QPI voltage, 1600mhz ram, 20 CPU multiplier, 7200GT/s QPI link speed, 200 BLCK, 1.7 DRAM voltage

I still cannot find the QPI Multiplier/Frequency... Any idea why I cant find it? It just doesn't show in bios

If you can manually set the QPI Link Speed, then you don't need the multiplier/frequency. The 7200 QPI Link Speed is what you were trying to accomplish anyway.

Did you try setting your RAM's command rate to 2T? Like I said, I had lots of instability until I did that. I could fiddle with voltages, CAS latency, or whatever, but until I lowered the command rate, it was flaky at best.

[years]

I even tried setting it to 3T (Or 3N which its called in my BIOS, same thing right?).. I tried 21 multiplier/190FSB/1550mhz/3T and it crashed after 10min. Now im back to running at CL 9-8-8-23 1N 1200Mhz, so i bit tighter timings, but still not worth it compared to 1600mhz and normal timings imo. This is so annoying, I dont get how they are allowed to sell sticks that cant do what they are supposed to do...