Weekend Tweaking : Pushing my E8400

[Triton05]

I managed to pick up a nice "SpotCooler" for my rig. Absolutely love it. It screws to one of your mobo mounts. It was exactly what I was looking for. I have it blowing across my memory and NB heatsink.



Ok heres where my hellish weekend begins!

I install my new fancy spot fan. My CPU under full load dropped about 4C. So now its time to see how high I can clock my E8400 on air with reasonable Voltages.

All voltages are from CPUZ under full load running IBT.

-----------------------
4.1Ghz vcore 1.34 / 2.4B strap / FSB 456 memory@ 1094Mhz tRD9 Dram 2.1v / IBT"High" 10 pass : success / Small FFT's 2hrs good / Large FFT's FAIL within 2min
-----------------------
4.2Ghz vcore 1.34 / 2.0D strap / FSB 467 memory@ 934Mhz tRD10 Dram 2.1v / IBT"High" 10 pass : success / Small FFT's 2hrs good / Large FFT's FAIL within 2min
-----------------------
4.4Ghz vcore 1.37 / 2.0D strap / FSB 489 memory@ 978Mhz tRD10 Dram 2.1v / IBT"High" 10 pass : unstable " No further testing at this speed " I go back to focusing more on 4.2Ghz
-----------------------

So I set everything back to 4.2Ghz. I try pushing my vcore to 1.36v. IBT and Small FFT's are fine once again. But as soon as Im doing Blends and it kicks off a Large FFT, hardware failure. So im thinking my memory is bombing out on me. Since Large FFT's actually stresses your Memory.

So I go into my bios, up my DRAM to 2.12v and up my MCH from 1.26v to 1.28v and boot back into windows.

Go to launch Prime95 Large FFTs' and BSOD. WTF!! confused.

I give up and set everything back to 4.05Ghz. Like I had prior. IBT tests fine, Small FFT's fine, but when I start a Large FFT's it fails almost immediatly. So now Im REALLY confused/frustrated.

I go online and read something about G.Skill memory actually not working well with high voltage. So hey, why not try something different.

I go into my BIOS, drop MCH to 1.24v and my Dram to 2.06v. Boot into prime95. Baddabing! Had Large FFT's running for well over an hour this morning before work without ANY issues. IBT HIGH did 10 passes without any issues. This is a 1.328 vcore.

So.. I have yet to tweak/tinker more. But Im wondering if I can keep my DRAM/MCH voltages low, and hopefully THAT will resolve my stability issues at 4.2Ghz+

My temps at 4.2Ghz in IBT were only topping at 70C which is fantastic since Prime95 never even breaks 60C now. This was with my vcore @ 1.34

Thoughts, Advice, Comments?

Thanks.

[Lsdmeasap]

Re: Weekend Tweaking : Pushing my E8400

Nice testing you are doing!

Yes, higher voltages can lead to instability just like not enough, something not everyone keeps in mind.

You didn't mention Vtt, this also has a large effect on stability and or what you can push your memory to, as does MCH Ref.

[Triton05]

Re: Weekend Tweaking : Pushing my E8400

vtt for 1.328v was 1.30
vtt for 1.344 was 1.32
vtt for 1.36+ was 1.34

It appears I had the ' CPU ' stable. Taking into account I passed IBT with flying colors and Small FFT's since that utilized JUST the L2 cache on the cpu.

It took a bit for me to realize that the Larget FFT's exceed the L2 cache size, so in that affect.. its stressing the CPU to memory bridge.

Right now, with my MCH at 1.24v I think its reference is .96v maybe? trying to remember off the top of my head.

Id love to get 4.1Ghz stable with the 2.4B strap. Talk about memory bandwidth! ;)

[Lsdmeasap]

Re: Weekend Tweaking : Pushing my E8400

You may want to try a lower Vtt as well, did you try that or do you think it always needs 1.3 or above at these speeds?

MCH ref must be set at 1.20Vtt, so .96 would not be what you should think of it as. At 1.20Vtt default is .76 MCH Ref, more or less while Vtt is at 1.20 is how you change it, then change Vtt back to what you want to use.

[profJim]

Re: Weekend Tweaking : Pushing my E8400

As I recall, some Gskill 4GB 1066 memory kits were only stable with MCH Core = 1.05 (this isn't a typo).
VTT (Cpu Termination) settings have a major effect on stability. Keep VTT lower than CPU Vcore, preferably by at least 0.05 volts.
Most E8400 setups at 4GHz or higher require tweaking MCH Reference (and sometimes CPU Reference) settings by lowering the setting by 1 - 3 clicks.
The basic procedure for this mod is:

1. Temporarily set CPU Termination (VTT) = 1.20
2. Make desired adjustments to either or both of these Reference settings (MCH Ref and/or CPU Ref).
3. Set VTT back to the desired setting

This procedure is from Lsdme's http://forums.tweaktown.com/gigabyte...-easytune.html thread.

[Triton05]

Re: Weekend Tweaking : Pushing my E8400

Ever since I OC'ed to 4.0Ghz, Ive had my Vcore @ 1.328 LOAD with LLC enabled. My Vtt was 1.30 and never gave me any issues. I always thought I was supposed to keep it a smidge under what my " Load " vcore value.

As for the MCH Ref. Like you pionted out, that scales with the MCH voltage. Right now with my MCH at 1.24v my MCH ref is either .96 or .98. Should it be higher, or lower? at the moment, Im back to being solid/stable at 4.05Ghz with my current spec's in my signature.

[profJim]

Re: Weekend Tweaking : Pushing my E8400

The general VTT guideline is that VTT should be at least 0.05 - 0.10 volts lower than the CPU Vcore setting.
I don't know if having LLC enabled alters the general VTT recommendation.

I wouldn't mess with your stable 4.05GHz setup, but if you want to o/c higher, you'll probably need to find the optimal MCH Ref setting.
Some claim that they also needed to lower the CPU Ref setting with higher overclocks with their Core2Duo setups.

[Triton05]

Re: Weekend Tweaking : Pushing my E8400

Thank you.

BTW, my G.SKILL PC8500 2x2GB 5-5-5-15 kit is rated for (2.0v-2.1v)
Well see how stability is tonight at higher CPU speeds with Dram voltage lower along with a lower MCH voltage.

Ill try 4.2Ghz with a Vtt of 1.30 and a vcore of 1.344 Load. Ill leave MCH at its current 1.24v and a put my dram to 2.0v. (since Ill be using the 2.0D strap, the memory will actually be underclocked. So it shouldnt have any issue at all posting at 2.0v)

This make sense?

[profJim]

Re: Weekend Tweaking : Pushing my E8400

Makes sense, but that doesn't mean it will work. ;)
You'll have to find the best balance of voltage settings, preferably by changing only one setting at a time.
Some other C2D Gskill overclocks were not at all stable with MCH Core settings in the 1.2x range, sometimes at somewhat lower o/c settings than your current 4GHz o/c.

Good luck with your large FFT tests.

[Triton05]

Re: Weekend Tweaking : Pushing my E8400

Makes sense, but that doesn't mean it will work. ;)
You'll have to find the best balance of voltage settings, preferably by changing only one setting at a time.
Some other C2D Gskill overclocks were not at all stable with MCH Core settings in the 1.2x range, sometimes at somewhat lower o/c settings than your current 4GHz o/c.

Good luck with your large FFT tests.

Thanks! Ill post an update tonight, or tomorrow after I get home from work and have ample time to tweak and test!

[Triton05]

Re: Weekend Tweaking : Pushing my E8400

Just got IBT 10 pass stable

4.2Ghz vcore 1.36 Load / vtt 1.32 / mch 1.24 / FSB 467 memory 2.0D : strap tRD 11 / dram 2.02v

I had to raise my vtt from 1.30 to 1.32 to get it stable and drop MCH ref to 0.72.

Processor: Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz
Clock Speed: 4.22 GHz
Active Physical Cores: 2
Total System Memory: 4094 MB

Stress Level: Standard (1024 MB)
Testing started on 8/16/2010 7:31:26 PM

Time (s) Speed (GFlops) Result
[19:32:04] 31.726 28.1751 3.628089e-002
[19:32:41] 31.321 28.5397 3.628089e-002
[19:33:19] 31.201 28.6496 3.628089e-002
[19:33:55] 31.273 28.5835 3.628089e-002
[19:34:31] 30.964 28.8683 3.628089e-002
[19:35:07] 30.958 28.8740 3.628089e-002
[19:35:42] 30.981 28.8522 3.628089e-002
[19:36:19] 31.223 28.6290 3.628089e-002
[19:36:55] 31.249 28.6055 3.628089e-002
[19:37:30] 30.994 28.8404 3.628089e-002

Testing ended on 8/16/2010 7:37:31 PM
Test Result: Success.
----------------------------

Onto further testing!

[Triton05]

Re: Weekend Tweaking : Pushing my E8400

Large FFT's fails immediate.

Dropped Dram voltage to 1.98v, just passed IBT. About to give Large FFT's another go. Keeping MCH ref and MCH core along with Vcore the same, since apparently THATS keeping me IBT stable..

[Triton05]

Re: Weekend Tweaking : Pushing my E8400

Im at a loss.

Bumped MCH to 1.26 I kept the MCH ref at 0.72 I can still pass IBT no problem. Now Prime95 isnt telling me its failing but Im getting an " application stopped working " and my only option is to close prime.

What does that mean?!

About to call it a night. *shrug* I feel like Im close...

[profJim]

Re: Weekend Tweaking : Pushing my E8400

The following template is from the D-an-W epic thread (889 posts) in his quest to o/c his E8400 using 2.0 volt Crucial memory:
http://forums.tweaktown.com/gigabyte...ot-450fsb.html

D-an-W 4.25GHz, 500 x 8.5
***************************************
***************************************
Gigabyte GA-EP45-UD3P (Rev. 1.0) - F10e
***************************************
***************************************

******************************
MB Intelligent Tweaker(M.I.T.) 
******************************
Robust Graphics Booster ..............: [Auto]
CPU Clock Ratio ......................: [8X]
x Fine CPU Clock Ratio................: +0.5
CPU Frequency ........................: [B]4.25GHz[/B]( 500x8.5)

********** Clock Chip Control ********

>>>>>  Standard Clock Control
CPU Host Clock Control................: [Enabled]
x CPU Host Frequency(Mhz).............: [ [B]500[/B]]
PCI Express Frequency(Mhz)............: [100]
C.I.A.2...............................: [Disabled]

>>>>> Advanced Clock Control..........: [Press Enter] 
CPU Clock Drive.......................: [800mV]
PCI Express Clock Drive...............: [900mV]
CPU Clock Skew........................: [  0ps]
MCH Clock Skew........................: [  0ps]

******** DRAM Performance Control ********

Performance Enhance...................: [Standard]
Extreme Memory Profile(X.M.P.)........: [Disabled]
(G)MCH Frequency Latch................: [Auto]
System Memory Multiplier (SPD)........: [[B]2.00D[/B]]
Memory Frequency(Mhz).....800.........: 1000
DRAM Timing Selectable (SPD)..........: [Manual]

>>>>> Standard Timing Control
x CAS Latency Time................5...: [5]
x tRCD ...........................5...: [   5]
x tRP.............................5...: [   5]
x tRAS...........................15...: [  15]

>>>>> Advanced Timing Control.........: [Press Enter] 
x tRRD............................3...: Auto
x tWTR............................3...: Auto
x tWR.............................6...: Auto
x tRFC...........................52...: Auto
x tRTP............................3...: Auto
x Command Rate (CMD) .............0...: Auto

>>>>> Channel A Timing Settings.......: [Press Enter] 
x Static tRead Value.............11...: [[B] 9[/B]]
x tRD Phase0 Adjustment...........0...: Auto
x tRD Phase1 Adjustment...........0...: Auto
x tRD Phase2 Adjustment ..........0...: Auto
x tRD Phase3 Adjustment...........0...: Auto

x Trd2rd(Different Rank)..........6...: Auto
x Twr2wr(Different Rank)..........6...: Auto
x Twr2rd(Different Rank)..........5...: Auto
x Trd2wr(Same/Diff Rank)..........8...: Auto

x DIMM1 Clock Skew Control (ps).......: Auto
x DIMM2 Clock Skew Control (ps).......: Auto
x DDR Write Training..................: Auto

>>>>> Channel A Driving Settings......: [Press Enter] 
x Driving Strength Profile............: [[B]1066Mhz[/B]]

x Data Driving Pull-Up Level..........: Auto
x Cmd Driving Pull-Up level...........: Auto
x Ctrl Driving Pull-Up Level..........: Auto
x Clk Driving Pull-Up Level...........: Auto

x Data Driving Pull-Down Level........: Auto
x Cmd Driving Pull-Down level.........: Auto
x Ctrl Driving Pull-Down Level........: Auto
x Clk Driving Pull-Down Level.........: Auto

>>>>> Channel B Timing Settings.......: [Press Enter] 
x Static tRead Value.............11...: [[B] 9[/B]]
x tRD Phase0 Adjustment...........0...: Auto
x tRD Phase1 Adjustment...........0...: Auto
x tRD Phase2 Adjustment ..........0...: Auto
x tRD Phase3 Adjustment...........0...: Auto

x Trd2rd(Different Rank)..........6...: Auto
x Twr2wr(Different Rank)..........6...: Auto
x Twr2rd(Different Rank)..........5...: Auto
x Trd2wr(Same/Diff Rank)..........8...: Auto

x DIMM1 Clock Skew Control (ps).......: Auto
x DIMM2 Clock Skew Control (ps).......: Auto
x DDR Write Training..................: Auto

>>>>> Channel B Driving Settings......: [Press Enter] 
x Driving Strength Profile............: [[B]1066Mhz[/B]]

x Data Driving Pull-Up Level..........: Auto
x Cmd Driving Pull-Up level...........: Auto
x Ctrl Driving Pull-Up Level..........: Auto
x Clk Driving Pull-Up Level...........: Auto

x Data Driving Pull-Down Level........: Auto
x Cmd Driving Pull-Down level.........: Auto
x Ctrl Driving Pull-Down Level........: Auto
x Clk Driving Pull-Down Level.........: Auto

****** Motherboard Voltage Control ******

Voltage Types..........Normal...........Current
-----------------------------------------------
>>> CPU
Load-Line Calibration.................: [[B][COLOR="red"]Disabled[/COLOR][/B]]
CPU Vcore..............1.27500V.......: [[B]1.38750V[/B]]
CPU Termination........1.200V.........: [[B]1.320V[/B]]
CPU PLL................1.500V.........: [1.570V]
CPU Reference..........0.760V.........: [Normal]
>>> MCH/ICH
MCH Core...............1.100V.........: [[B]1.320V[/B]]
MCH Reference..........0.760V.........: [[B]0.796V[/B]] [U](0.720V with CPU Termination @ 1.200V)[/U]
MCH/DRAM Reference.....0.900V.........: [Normal]
ICH I/O................1.500V.........: [1.500V]
ICH Core...............1.100V.........: [1.200V]
>>> DRAM
DRAM Voltage...........1.800V.........: [[B]2.020V[/B]]
DRAM Termination.......0.900V.........: [Normal]
Channel A Reference....0.900V.........: [Normal]
Channel B Reference....0.900V.........: [Normal]

******** Advanced BIOS Features ********
Hard Disk Boot Priority...............: [Press Enter]
First Boot Device.....................: [USB-HDD]
Second Boot Device....................: [Hard Disk]
Third Boot Device.....................: [CDROM]
Password Check........................: [Setup]
HDD S.M.A.R.T. Capability.............: [Enabled]
Limit CPUID Max. to 3.................: [Disabled]
No-Execute Memory Protect.............: [Enabled]
CPU Enhanced Halt (C1E)...............: [Disabled]
C2/C2E State Support..................: [Disabled]
x C4/C4E State Support................:  Disabled
CPU Thermal Monitor 2(TM2) ...........: [Enabled]
CPU EIST Function.....................: [Disabled]
Virtualization Technology.............: [Disabled]
Delay For HDD (Secs)..................: [ 0]
Full Screen LOGO Show.................: [Disabled]
Backup BIOS Image to HDD..............: [Enabled]
Init Display First....................: [PEG]

******** Integrated Peripherals ********
USB Keyboard Function.................: [Enabled]
USB Mouse Function....................: [Enabled]
USB Storage Function..................: [Disabled]

YMMV

[Triton05]

Re: Weekend Tweaking : Pushing my E8400

I was up far longer last night then I should have been! Unfortuantely, I just couldnt get the Large FFT's stable for longer then 10min @ 4.2Ghz.

My best run was with my MCH core at 1.16v and my MCH ref at 0.72v along with my Dram at 1.84v. Apparently, the higher the FSB the more unstable it became with higher voltage through the MCH. So your caught juggling CPU stability and Memory stability. I just couldnt have both :(

I decided to cut my losses and settled for this >

4.05Ghz @ 1.328v vtt 1.30v // MCH 1.24v MCH ref 0.76v // 450 FSB Dram 2.04v // 2.4B strap 5-5-5-15 tRD 9 running at 1080Mhz //

IBT max temp 61C
Prime max temp 55C
Idle temp 30C