SOLVED Problem with Corsair CMT12GX3M3A2000C9

[Arkade]

Hello, have the Corsair CMT12GX3M3A2000C9 kit running on my 920 right now. Mother board is a P6T. Issue i'm having is once the rams speeds reach about 13xx whatever stick is in slot B1 disappears. once i hit about 19xx then the one in C1 disappears, leaving me with 4GB. Is my 920's memory controller having a heart attack? or is this a ram issue? If ram, is it incompatible or bad ram. Thanks. First time i have ever seen this issue. Ram still shows up in CPUZ though, haha.

 

[Woomack]

You have to set QPI/VTT voltage higher. It also depends how high is bclk. If you go for 200-210MHz bclk then try something like 1.35-1.45V for 1600-1700 memory. For standard clock up to 1.25V should be enough.
1900-2000+ memory is usually waste of time on these platforms just because you have to set much higher voltage and it's hard to stabilize. Performance is about the same as with tighter timings on lower memory clock like 1600-1700.
Best balance seems something like higher bclk ( 200-210 ) and 1600-1680 memory clock on tighter timings like 6-8-6, 7-7-7, 6-7-6. For your kit it should work at least at 8-9-8-24, maybe tighter.

 

[Arkade]

Hey. I Believe i have tested increasing the QPI Voltage. I'm aiming for about 19XX and my BLCK is 195. Anything more and it won't post. Will try QPI Again using around the numbers you gave. Thanks.

 

[Woomack]

To set ~2000 or higher you may need 1.5-1.55V+ QPI/VTT. It's fine for benchmarks but too much for 24/7. Also try IOH up to 1.2V.

 

[Arkade]

I belive my IOH is 1.2 and my ICH is 1.4(or vice versa, i'm tired and forgot how i set it up) but i will try increasing the QPI. I Thought i set it to 1.35 but i could have forgotten. Haha. So busy doing other stuff. Thanks for the help. Will get back to you when it's fired up. Working on my PWM controller and new CPU Cooler.

 

[Arkade]

Well, i tried bringing the QPI almost all the way upto 1.59 volts. nothing. Although it seems that since i last tried, I get 8 GB at 19XX on the memory speeds. My Base Clock is 195mhz(multiplier 21 for CPU). Any other ideas(Dram Bus voltage is 1.66, shouldn't need more as that is corsair spec)

 

[Woomack]

It's not guaranteed that you make 2000+ memory clock. Memory controller in i7 920 is supporting DDR3-800/1066 so anything higher is already overclocking. Your board is supporting memory up to DDR3-1333 and anything higher is overclocking so not guaranteed by producer.
Thats why I said that something about 1600-1700 memory clock is optimal for this platform. It's about highest clock which is stable on most of these cpus. It's also giving about the same performance as DDR3-2000 just because you can set tighter timings.
Other thing is that on ASUS boards it's harder to stabilize higher memory clocks. ASUS generally needs higher QPI/VTT than other brands on X58 chipsets.
Next thing is that you are using 4GB sticks that are stressing memory controller more than 2GB sticks.
Gulftown cpus have better memory controllers so it's easier to set higher memory clock.

I would try to set cpu using 210MHz bclk and memory @1680 8-9-8 ( tighter can be hard ).
I was actually running 4x4GB Crucial Elite @1680 7-7-7-20 with i7 950@4GHz ( 19x210 ). 4 sticks but triple channel was working fine

 

[Arkade]

Hey. Is increasing memory size the culprit? My last kit was 3GB of ram and was running 1914 mhz no problem. Forgot the Corsair number, but I can find out if you give me some time to get them out of my parts bin. It's always the ram in slot B1 which is why I assume it's the memory controller. Going to grab my 965(Currently in my Super Secret Surprise ) and see if I have better luck. Will post results later. Also, want to try setting the command rate to 2T, it's currently on 1T.(although my speed is 11XX mhz ): )

 

[Woomack]

Generally higher memory density = lower max clocks as it's harder to stabilize memory controller. So 6GB ( 3x2GB ) will much easier make 2000+ than 12GB ( 3x4GB ). But usually 12GB/6x2GB = 12GB/3x4GB as it's also harder to stabilize 6 memory sticks than 3 on these boards.
Command Rate 2 is usually required to make higher clocks on 4GB sticks but that depends from memory controller and used IC. Still good to try.

 

[Arkade]

Would Different Ram possibly make a difference?(Crucial Ballistix Tracer 3X4 12GB 1600 kit?)

 

[Woomack]

Not worth to change. Better think about newer platform as on X58 0-2% performance more isn't worth new memory kit.

 

[Arkade]

I Would never change platforms. Not with the work I've put into this machine. Also it's because i can return the ram kit and get the crucial one(i have 30 days left for a return) which is cheaper, and looks awesome

 

[Woomack]

http://www.overclockers.com/forums/showthread.php?p=7160067#post7160067
Crucial Ballistix Elite 1600 8-8-8-24 1.50V, 4GB sticks.

These were working on my X58 board as 1680 7-7-7-20 1.64V and I had 4 sticks running in triple channel ( don't know if 4 sticks will work on P6T board so better get 3 ).
1600 Elite series have about the same chips as 1866 Elite or 1600/1866 Tactical. Maybe even better will be to get 1866 as is higher chance for better chips and price isn't much higher ( depends from store ).

I also checked that 2x 1600 Crucial LP 8GB sticks were working fine even though 8GB sticks are officially not supported on these boards. I don't know if 3 or more will work.

I replaced board and cpu lately more because of compatibility issues and power usage than that I needed faster cpu. These i7 are still fast enough for everything even though have about 3 years.

 

[Arkade]

Gonna give the RMA ram a shot. If it fails, i'm gonna return it, and get the Crucial kit. BTW, i think i have bad sticks now because today, at 11xx mhz the stick in B1 is now invisible. Will let you know in a week or so how the RMA goes(just finished the Advanced RMA Process)

 

[Arkade]

Just in case, i also got a different mobo.

 

[Arkade]

Weird, but it was my motherboard. I order another P6T and this one is running triple channel at 19XXmhz. Guess the RMA goes back now, haha.