F3-16000CL8T-6GBPS unstable @ 2000mhz.Need very high QPI/DRAM Voltage to run stable.

[bager4e]

Hello dear colleagues and friends,

This is my first post here , because I have problem and i can't solve it.

For many years I'm using G. Skill memory and I'm very happy. I never had even a single problem. Strong performance, very stable...

My memory is : G.Skill F3-16000CL8T-6GBPS (6GB 8-8-8-21-1T , 2000Mhz)


The first memory that I bought was defective. The problem was that one of the sticks was "Invisible" and the Bios and OS saw only 4GB. But CPU-z and Everest recognize all 6GB. Otherwise this Kit worked with normal QPI/DRAM - 1.35v @ 2000Mhz.And memory was replaced with a new Kit.


Now with the new Kit I have following problem:
This Kit need VERY high QPI/DRAM voltage to run stable. I need more than 1.65volt to
run my memory @ 1800Mhz ( 8-8-8-21). For 2000 , more than 1.75volt (RED).
I run Prime95 with the following settings:
CPU 180x20 ( 3.6GHz) 1.325v
RAM: 1814Mhz ( 8-8-8-21@1T) 1.65v
QPI/DRAM voltage 1.65v

And after 4 hours stress system has crashed with Blue screen. I repeated this experiment
several times ( increases Cpu Vcore - 1.35 - 1.375).- same result

My CPU is Core i7 920 D0 Revision and this cpu is very good overclocker. I reach 4.49 Ghz on air with other memory ( 3x2GB Kingston 1600Mhz 9-9-9-27). The Kingston Memory was overcloced to 1800Mhz and Qpi was 1.375 V.
I rаn prime95 @ 4Ghz - rock stable. ( with Kingston)



My Configuration is:

MB: Asus Rampage2 Extreme ( BIOS Version 1504, latest)
CPU: Intel Core i7 920 D0 / PT Megahalems.
RAM: G.Skill F3-16000CL8T-6GBPS ( 8-8-8-21 @ 2000Mhz , 1.65v)
VGA: Asus ENGTX295
HDD: 2x1TB Raid0 WD1001FALS
CDROM: Asus DVD+RW 2014S1T
PSU: CM Real Power 1250W
Case : HAF922


I need advice on what to do.
New Memory? New Bios?
I think that this is very high voltage for QPI/DRAM and this is not safe for the CPU.

Thanks in advance!

Best Regards,

bager4e

[Tradesman]

ASUS just recently changed the advertising on this board to raise the RAM speed rating to 2000. (probably only checked a couple three types of RAM), you may need to loosen the timings to maybe 9-9-9-24 or 9-9-9-27 is my first thought, you have the latest BIOS (1503 8/18/2009) so they should have a new update coming out in the next week or so.
Other thoughts would be to raise your tRFC and possibly the tRC, what are those at now?

[bager4e]

Hi ,

Thank you for your quick answer.


tRFC is 88 or maybe 90
tRC - no idea , i will check tomorrow because I have no access to my configuration right now.

I will try with 9-9-9-24. ( 1T or 2T? ).
I will give a feedback tomorrow.

Can you tell me please what is the max safe voltage for QPI/DRAM?
And good values for tRFC and tRC for this memory. I will test...

10x

[Tradesman]

First if you are currently at 1T command rate, try 2T. tRFC is prob good at 88, but will depend partly on tRC. If at 2T now, try 9-9-9-27 first, if that works drop to 9-9-9-24. Specifics for this mobo I'll have to check, will get back later this PM.

[bager4e]

I try 2000Mhz ( 9-9-9-27 at 2T) , and QPI/DRAM 1.45V and OS crash immediately.
Test with 1.55 V - system crash without stress test after 2-3 min runing OS.



Some settings ( test 1 , QPI 1.45V / 9-9-9-27 at 2T) :

DRAM Timings:



Voltages:





Now testing with 1.6V QPI/DRAM ( 2000 Mhz ,9-9-9-27@ 2T)....
Running Prime 95 15 min.... (Cpu Core Temps ~ 68 -72 C , Load 100% )
No problem so far....

[bager4e]

1.6V QPI/DRAM ( 2000 Mhz ,9-9-9-27@ 2T)

CPU 3.6Ghz (200x18)

Crash after one hour prime 95.

://

[GSKILL TECH]

Try these settings:


AI overclock - manual
OC from CPU level up - auto
OC from Memory level up - DDR3-2000
CPU Ratio setting - 18 for 3.6GHz
CPU Turbo Power Limit - disable

CPU configuration
CPU Ratio Setting - 18
C1E Support - disable
Hardware prefetcher - enable
Adjacent Cache line prefetcher - enable
Intel Virtualization tech - disabled
CPU TM Function - disable
Execute Disabled bit - disabled
Intel HT Technology - disable
Active Processor Cores - all
A20M - disabled
Intel C-STATE tech - disabled

BCLK frequency - 200
PCIE frequency - 100
DRAM frequency - 2000 MHz
UCLK frequency - 4000 MHz
QPI frequency - auto

Dram Timing Control
DRAM CAS# Latency - 8
DRAM RAS# to CAS# Delay - 8
DRAM RAS# PRE Time - 8
DRAM RAS# ACT Time - 21
DRAM REF Cycle Time - 74
DRAM Timing Mode - 2N
All others can be on AUTO

EPU II Phase Control - Full Phase
Load-line calibration - enable
CPU differential amplitude - auto
Extreme OV - disabled


CPU voltage - 1.34V
CPU PLL voltage - 1.85V
QPI-DRAM voltage - 1.55V

IOH voltage - 1.35V
IOH PCIE voltage - 1.60V
ICH voltage- 1.20V
ICH PCIE voltage - 1.60V

DRAM Bus voltage 1.65V

CPU spread spectrum - disabled
PCIE spectrum - disabled
CPU clock skew - auto
IOH clock skew - auto

Let me know how that goes.

Thank you
GSKILL SUPPORT

[bager4e]

Thank you for your answer.

I will test with these settings and post the result here.

[bager4e]

Hi again.

With these settings my system crash by booting OS. Immediately. You can see interactive what's happening:

http://bager4e.fs-bg.com/pics/pc-test/06102009036.mp4

Found(again) that the stability of my system(with this kit) depends only on QPI/DRAM voltage. By 1.45v - no chance to boot OS.
(

[GSKILL TECH]

Yes, with BLCK 180 you will need 1.50V, BCLK 200 will need 1.55V+. You can try lowering the BCLK and maximizing the memory multiplier.

Thank you
GSKILL SUPPORT

[bager4e]

With these settings system crash (prime 95) :

CPU 180x20 ( 3.6GHz) 1.34v
RAM: 1814Mhz ( 8-8-8-21@1T) 1.65v
QPI/DRAM voltage 1.65v !!! Lower then 1.65 - its no good.
(If QPI 1.55 -1.6v - no chance to Boot OS, or system crash without stress test)

########

Lowering the BCLK:

With BCLK 160 and QPI 1.55v system crash immediately .
If QPI is more then 1.65v ,system is stable for a longer time and can boot...

Now testing with BCLK 160 and 1.65v QPI ( prime 95)
CPU speed is 167x21 3.507Ghz.
Core tems are 62 -67 C ( 100% load)
No problem so far , but I think that 1.65v is VERY high ....

//For this CPU 4 or 4.2Ghz is not a problem. I want to run @ 4 or 4,2 ( 24/7). And I will need BCLK 200. But first need to fix this issue with the RAM.//

Thank you

[bager4e]

With BCLK 180 and QPI 1.5v OS can't boot.
BCLK 180 and QPI 1.6 volts , OS crash after 2-3 min ( idle)

Lowering:

With BCLK 160 and QPI 1.61V OS crash after running prime95 ( 1-2 min)


Now testing with BCLK 160 and QPI 1.65V ( prime 95).

Everything below this voltage is very unstable.


But QPI more that 1.55v seems to be dangerous...

[GSKILL TECH]

Dear Customer

Have you tried testing each memory module individually? You may have a bad stick causing you the issues. Otherwise this motherboard and CPU should have better results than what you speak of. Please let me know the results and I will be able to further assist you.

Thank you
GSKILL SUPPORT

[bager4e]

Thank you for your answer.

One of the sticks has filed today! It's not recognisable any more. System can't boot with this module(Test this module in any slot alone). With other 2 modules system can boot.
if I put all modules then the system recognizes only 4GB. Just like the first Kit.

Now testing with Corsair TR3X6G1600C8D G

QPI / Vtt 1.35v
CPU 200x20 ( 4.0Ghz) , 1.38v
RAM : 1600Mhz 8-8-8-24 @ 2T



Seems to be ok with 1.35 QPI/VTT

But Corsair performance is much lower then G.Skill..... ( Everest memory test , etc)

Just remember this is my second Kit:
The first memory (G.Skill) that I bought was defective. The problem was that one of the sticks was "Invisible" and the Bios and OS saw only 4GB. But CPU-z and Everest recognize all 6GB. Otherwise this Kit worked with normal QPI/DRAM - 1.5v @ 2000Mhz. Now I have the same issue,,,

Lack of luck maybe...

[GSKILL TECH]

Everything shows up fine with the Corsair? You may want to try a different motherboard if you are having the same issue with two sets.

Thank you
GSKILL SUPPORT