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i think this may be a limitation of the processor. The 920 and 940 should only be able to go up to 1066mhz. the XE 965 seems to have the memory controller speed unlocked.
I find it strange that you are even getting 1333.
My memory was running fine at 1866 Mhz, even at 1925 Mhz there was no problem on his machine, and he also have the X58 Rampage ll Extreme, and also i920.
Now i am trying to run only one stick, but it stil won´t work...
(FPO/BATCH #: 3836B175) If this may be usefull..!
I hate my life, -just a little bit
The standard I7 models 920 and 940 does NOT have locked memory multipliers. However there are certain "built in" limitations. A few examples:
1. The uncore can't run faster than the nominal clock frequency
2. Memory can't run at more than half the frequency of the uncore.
3. For every extra DIMM per channel you need to lower frequency. For example: 1333 MHz can be used for 1 (ONE) DIMM per channel and 3 (THREE)
channels. With 2 DIMM's per channel you need to use 1066MHz.
4. Look at the "qualified vendors list" for your ASUS motherboard. You will see that 1866mhz modules are poorly supported. You need to raise the voltage to dangerous levels on the memory interface. Its based on shoddy engineering.
Did you know this: A lot of Corsair 2GB ddr2 memory modules uses a Tref of 105ns instead of the correct 127.5ns ? The simply didn't adjust this parameter when they went from 512mbit to 1Gbit technology. I simply don't trust them. You need to double check every parameter.
But it's actually ungreatfull to buy the fastest CPU on the marked and then ask for MORE than it's designed for. So the person at fault is YOU.
ASUS also cheats. For example with the "turbo mode" on i7 boards. It actually invokes "power vr override" ! That means your CPU is no longer limited to 130W. A 920 goes to around 150W!
Those two settings should NEVER be used simultaneously according to Intels way of thinking. However ASUS has a completely different mindset. And never the twain shall meet.
A few minutes ago i powered up my machine, with it my new CPU, and everything ran great, i am right now doing 1600Mhz without any problems, -so i am a happy man now.
My 1. CPU was S-spec number: SLBCH. This is rev. C0 (Batch#:3836B175)
My new CPU is S-Spec SLBEJ and rev. D0.
The CPU swop was the only thing solving my problem.
I don´t know how much you have tried adjusting in BIOS, but some things are important: Correct ram timing (look on the modules to see the first 4 "example 9-9-9-28" or www. for more values) QPI/Dram voltage about 1,35 voltage and 1,65 DRam voltage. These settings should be enough to get mem. speed up, but if this dosen´t work, check your BATC# (written on box)