CMT6GX3M3A2000C8 XMP Profile doesn't post!

I just bought this kit CMT6GX3M3A2000C8 recently and i can't post at 2000MHz using XMP. I'm running a i7 920 on a Asus Rampage II Extreme OC'ed to 3.8GHz i have no problem posting and booting using a lower clock like 1600MHz but 2000MHz just won't go.

I'm using CPUTweaker (another freeware similar to CPUz but with more Timings details) and here is what XMP#1 (2000MHz) Timings looks like on CPUTweaker:

http://img185.imageshack.us/img185/5431/referencia.jpg

From all these i know how to setup manually CL: 8 tRCD: 9 tRP: 8 tRAS 24 CR 2T (these are also loaded by default when you choose to overclock by XMP on BIOS)

but the rest i don't know how to manually configure, they don't make sense to me. I would appreciate if someone could translate what the following values mean:

tRC: 51

tRFC: 110

tRRD: 8

tWR: 15

tWTR: 8

tRTP: 8

tREF: 7.8 us

I think those are the last details i need to manually enter at BIOS so to boot properly at 2000MH but i don't know what each mean.

Also DRAM Bus Voltage is at V1.65v what Voltage should QP1/DRAM be set at? My Rampage II is updated to the latest BIOS 1802..

Thanks!

I'm on the same boat as you, I got my system to boot with the memory at 2000 Mhz but only after a huge increase of QPI Voltage.... XMP profile set QPI Volt at 1.25 Volts which didn't even post, the system booted with XMP after raising QPI volts at 1.5 i think, I i'm not using the XMP anymore since I'm aiming for a 4.0 Ghz CPU overclock also. I Raised QPI Volts to 1.6 Volts after some reading as well. I'm testing for stability at the moment to see if i can get the system stable at 4 GHZ CPU 2000 Mhz Ram, after that i'll try to lower the voltages since my temps are a bit high now (around 88 Degrees while testing with intelburn test)

let me know how it goes for you.

Hi atinoco,

Yeah I previously posted in your thread but deleted my post to avoid unnecessary clutter and confusion so i created this thread, thanks for sharing your experience and tips :)

Hi Yellowbeard thanks for helping :) OC'ed or at stock i can't post at 2000MHz. Currently i'm running CPU at stock (2.6GHz) and the CMT6GX3M3A2000C8 kit at 1066MHz.

I'm going to reboot here and give it another go in the BIOS i just found an article on techpowerup ( http://www.techpowerup.com/printarticle.php?id=131 ) explaining the extra timings i didn't understand. I'll try to input these aswell and see how it goes. Be right back!

EDIT: I managed to post now OC'ed to 4.0GHz and 2000MHz clock on the CMT6GX3M3A2000C8 kit. Still i'm having blue screens and some weird instabilities (CPUTweaker just crashed now) but i guess some voltage fine tuning will solve it.

Here's what i added to the DRAM Timing so i could post:

tRFC 110

tWR 15

tRTP 8

Currently i'm OCed to 4.0GHz and 2000MHz RAM. I'm gonna try to stabilize the machine on this setting. The bad thing is i got an older i7 920 (C0/C1 Revision) wich requires more voltage than modern revisions.. this is gonna be a bit tricky.

be carefull, i was just doing some stress testing with intel burn in test, I had the system overclocked to 4 Ghz and the ram at 2000Mhz , I was testing with 1.3 CPU core voltage. I increased the QPI Voltage to 1.65, the system booted and I fired up Intelburn test. after a couple of minutes the system powered down suddenly. the CPU temps last time i saw them were not that high, they were around 88 degrees max Now the system doesn't start at all, I cleared the Bios using the jumper, removed the battery, tried the switch bios feature and nothing.... when I hit the power switch the fans move just a bit, like the system is about to start, but then it shuts down. looks like something blew...

darn, this sux

Yeah you gotta be extra careful when OCing..

You said 88 degrees? Is that Celsius or Farenheit?

Here CPU Temperature is 29C Core 0 43C

i'm at 4007.9MHz Vcore oscillating between v1.37 and v1.39 (must be one of those dynamic transition tech of Intel i forgot to disable on BIOS)

Also: DRAM at v1.65 and QPI at v1.61

I think i'm going down to 3.8GHZ not worth risking anything with this old 920 revision C0.

Does your Motherboard comes with a LCD Poster? It may tell you what's going on when you power it up and it turns off...

Are you sure you're not confusing the QPI with the DRAM Bus Voltage?

Because when you set the DRAM Bus Voltage above v1.65 you get a warning in red on BIOS meaning you're violating intel specs and it's extremely dangerous to do it while in the other hand setting QPI at v1.65 you get a yellow warning meaning it is at medium voltage level.

Plus the XMP memory profile #1 of this kit automatically sets QPI and DRAM Bus Voltage at v1.65 to work at 2000mhz plus also overclocks the i7 CPU clock a tiny bit from 2.6 to 2.7ghz in order for this to work by default. And also.. if i set the QPI lower than v1.50 my memory kit won't post anyway (at 2000mhz i mean) but at a lower clock no problem.

EDIT: Forgot to say this before but a lot of folks are having problems using the XMP profile #1 of this kit ( CMT6GX3M3A2000C8 ) and are not able to post, i think the solution would be to implement the following values to the XMP profile #1 in order to post properly on the fly:

tRFC 110

tWR 15

tRTP 8

be carefull, i was just doing some stress testing with intel burn in test, I had the system overclocked to 4 Ghz and the ram at 2000Mhz , I was testing with 1.3 CPU core voltage. I increased the QPI Voltage to 1.65, the system booted and I fired up Intelburn test. after a couple of minutes the system powered down suddenly. the CPU temps last time i saw them were not that high, they were around 88 degrees max Now the system doesn't start at all, I cleared the Bios using the jumper, removed the battery, tried the switch bios feature and nothing.... when I hit the power switch the fans move just a bit, like the system is about to start, but then it shuts down. looks like something blew...

 

darn, this sux

Well after some thorough testing I realized that I didn't burn my CPU, the source of my problem was a faulty motherboard that died after 5 days of use see this thread at the Asus Forums: Did I Burn my new system? Please help....

I had another motherboard (Asus P6X58D-E) here so I'm up an running again.

I Followed the advice of this thread and I got the memory running at 2000 Mhz, (No CPU OC yet) here's what I did:

1- Load Bios Defaults

2- Loaded XMP in the Bios Tweaker

3- Got the Complete SPD settings from CPUtweaker (there's a jpg posted here also)

4- Manually set the items that were not set by the XMP automatically (like tRFC 110, tWR 15, tRTP 8 and any other that I saw of the SPD image that could be set manually)

5- Set QPI/VTT Voltage to 1.5V, it was set to 1.4V by default but windows was not stable (got a BSOD right away).

6- Testing with Prime95 as I post this to see if it's stable, it's been like 20 mins and it's looking good. will update this after it's 100% stable

I'm happy that it worked for you atinoco!

I think it would be best if Corsair updated the CMT6GX3M3A2000C8 kits with a new XMP#1 profile with all the extra timings (tRFC, tWR and tRTP) so people can post at 2000MHz with no hassle and on the fly. I'm currently stable at 3.8GHz BCLK 200, CPU Multi 19x (CPU VCore at 1.296) Memory at 2000MHz (QPI 1.65v and DRAM Bus 1.65v).

After what rjbarker mentioned about the risks of running a higher QPI i had to Google again just to be sure and i found again the overclock article on ASUS forum ( http://vip.asus.com/forum/view.aspx?id=20081220191040237&board_id=1&model=P6T+Deluxe&page=1&SLanguage=en-us )which i used to learn about OCing previously, stating that memory kits running at 2000MHz DO require a QPI of 1.65 to work whereas another kit with a lower clock (1600MHz) will work fine with QPI of 1.35v

I tryed using a QPI of 1.50v though i was able to post but i had BSODS on Win7 x64 then i came back to 1.65v and now i'm "stable" (no prime95 tests yet but already played a few games and some heavy multi-thread processing with an audio editor) and the PC is running for about 6hrs straight no blue screens of death :)

Just woke up and the system, it's still up and running after about 10 hours of prime95, so i guess it's stable.

you should run some stress tests to be sure your pc it's 100% stable, here's what I'm doing now to test stability, it might be overkill but I'd like to be 100% sure.

1- Test With IntelBurn Test (make sure you set it to run 8 threads so it runs all cores at 100%), 5 passes at very high for a quick test.

2- Then I do 25 passes of IntelBurn Test at very high (takes an couple of hours)

3- Then Prime95 (blend test) overnight or more.

I will be overclocking my CPU also but I'm leaving for a trip soon, so It'll have to wait for a month until I come back.

-Andres

Just thought I'd share my own experience with this particular RAM along with the others here. So that others may would up finding it to help them as it did in my case.

On my board, the R2E, XMP profile is really not setting the proper QPI voltage. Way too low at 1.25v (I think - I forgot the specific on the 2nd digit there).

BUT only upping the QPI voltage from 1.40v up to 1.55v got me nowhere. Still would not post. Also, just manually putting the supposed tRFC 110 - tWR 15 - tRTP 8 on said voltage levels does not work.

It would only post after I changed the tRTP to 11, like RAMGUY recommended.

At that point, 1.45v on the QPI got me several crashes just booting up.

Currently on 1.5v QPI, stable for 3.5 hours Prime95.

You might wanna try the same thing ACIDtek. I read too much voltage on the QPI is said to kill either the voltage regulators on the Mobo or the CPU.

BTW, anyone care to comment whether running these things at said speed/voltages is going to viable for long term 24/7 application?

Although I sincerely doubt I'll be going at it more than 12-16 hours stretch at a time max.

Quick update here:

While prime95 run flawlessly for 12 hours+, PC reboot indicates a problem.

It won't post unless I turn power off first.

I've now gone from 1.5v QPI to 1.55v QPI.

This seems to have fixed it... although I'm rather worried on the use of such high voltage power...

Skratch that, still having post problem sometimes.

Going to 1.60v QPI now.

Is there any other setting I should try out instead of just increasing the QPI voltage like this?

The link below may be useful reading:

http://www.techreaction.net/2010/09/07/3-step-overclocking-guide-bloomfield-and-gulftown/

So.... basically, the highest safe voltage for QPI is 1.45v?

It's also indicated that that's the highest one should go on 'air cooling'.

I'm on water... how high could I go safely?

Or is there another setting I need to change?

Last time, I need to change tRTP to 11 just to post in anything higher than 1600. (increasing voltage in QPI last time did not help with the 'no post', I tried it up to 1.55v)

Would increasing this particular setting further help me post?

Currently, prime95 is completely stable on XMP setting + tRTP 11 + QPI 1.50v.

The only problem is that quite a few times I need to boot it twice to post.

... maybe not such a big problem, but it gets annoying.

I'm throwing the towel here.

Already gone as high as 1.65 and I just had 2 bootup failure yesterday.

If I increase it any further, I'm afraid I'll start breaking things.

mine stops dead at 1602mhz if i try to go higher no matter how much VTT i feed it it will not POST i gave up and im going to RMA it if they ever get back to me.

Also as it was explained to me by a few other people its not my IMC thats weak +100 VTT gave me 1600mhz so the problem lies now the RAM doesnt want to run above 1600.

mine stops dead at 1602mhz if i try to go higher no matter how much VTT i feed it it will not POST i gave up and im going to RMA it if they ever get back to me.

Also as it was explained to me by a few other people its not my IMC thats weak +100 VTT gave me 1600mhz so the problem lies now the RAM doesnt want to run above 1600.

That's nowhere close to enough VTT to run 2000 on a Bloomfield core CPU. You may need as high as 1.6v QPI/VTT to run 2000. It will depend on your individual CPU/IMC.

So what about the XMP not working do i have to manually set the voltages with that too?

Thank you for replying yellowbeard was afraid tech support didnt care.

Heres a question for ya performance wise since my RAM is presently at 7-8-7-20-59 2T 1616mhz am i going to really gain anything by going to 1800ish mhz since i would have to up my divider as i don't want to OC my CPU atm

side note question my H70 sounds like a fish tank water pump is that normal?