Help requested with stabilizing E8400 / P45-DS5 @ 3,87GHz

[Jay8tsj]

Hey all,

I'm in the process of OC'ing my E8400 for the first time. I have manged to get it near stable @ 3.87GHz now without crossing over any max voltage settings as adviced by Intel.
I stressed my system with both Orthos and Prime95. Orthos continued for 5hrs without errors. On Prime 1 core errored after exactly 2hrs, the other was manually stopped after 9,5hrs without errors. I am hoping to get it rock sollid on Prime as well, and was hoping to get some advice.

These are my settings:

MAIN
CPU Frequency.................3870
CPU Clock Ratio...............9
CPU Core Speed................3869
FSB...........................430
FSB (Rated)...................1720
Advanced Clock Control
- CPU Clock Drive.............800mV
- PCI Express Clock Drive.....900mV
- CPU Clock Skew..............0
- MCH Clock Skew..............0
VOLTAGES
CPU
- CPU Voltage.................1.36250
- CPU Termination.............1.240
- CPU PLL.....................1.560
- CPU Reference...............0.816
- CPU Reference 2.............0.825
MCH/ICH
- MCH Core....................1.280
- MCH Reference...............0.785
- MCH DRAM Reference..........AUTO
- ICH I/O.....................1.560
DRAM
- DRAM Voltage................2.1
- DRAM Termination............AUTO
- Channel A Reference.........AUTO
- Channel B Reference.........AUTO
DDR SETTINGS
MCH Frequency Latch...........400
Sys. Mem. Multi. (SPD)........2D
FSB:DRAM Divider..............1:1
DRAM Frequency................430 (860Mhz)
CAS Latency Time (CL).........4
RAS to CAS (tRCD).............4
RAS Precharge (tRP)...........4
Precharge Delay (tRAS)........12
Advanced Timing Control
- tRRD........................AUTO
- tWTR........................AUTO
- tWR.........................AUTO
- tRFC........................AUTO
- tRTP........................AUTO
- Command Rate................AUTO


I have disabled all unnecessary features in BIOS, like C1E and EIST. PCI-X is fixed at 100MHz.

Anything I am supposed to change to get it rock solid on Prime95? Anything I should lower since I have built in too much slack?

[Jay8tsj]

Re: Help requested with stabilizing E8400 / P45-DS5 @ 3,87GHz

Hey all,

Altho you guys have been too busy to help me on my way directly in this thread, the multitude of posts on this forum have helped me in establishing a nice OC. I'm hereby posting my results so I might be able to do the same for others.

I managed to get a stable setup with the settings listed below. I didn't yet try if higher FSB settings will run stable on these voltages; for me this setup provides a baseline before making my way up (and hopefully over) the 4GHz treshold. My goal is to keep VCore close to 1.36250, as I favor prolongued useage over 100 extra MHz.

My system was stable over 18.5 hrs of blend testing with Prime95. Stress temps didn't exceed 49C.

SETUP

MAIN<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>
CPU Frequency.......................................3. 830MHz<o:p></o:p>
CPU Clock Ratio......................................9<o:p></o:p>
CPU Core Speed......................................3834.30 Hz (CPU-ID reading)<o:p></o:p>
FSB .................................................. .......426<o:p></o:p>
FSB (Rated)........................................... ..1704.1<o:p></o:p>
Advanced Clock Control<o:p></o:p>
- CPU Clock Drive ...................................800mV<o:p></o:p>
- PCI Express Clock Drive........................900mV<o:p></o:p>
- CPU Clock Skew.....................................0<o:p></o:p>
- MCH Clock Skew....................................0<o:p></o:p>
<o:p></o:p>
VOLTAGES<o:p></o:p>
CPU<o:p></o:p>
- CPU Voltage........................................... 1.35625<o:p></o:p>
- CPU Termination....................................1.2 40<o:p></o:p>
- CPU PLL............................................... ...1.500<o:p></o:p>
- CPU Reference.......................................AU TO<o:p></o:p>
- CPU Reference 2....................................AUTO<o:p></o:p>
MCH/ICH<o:p></o:p>
- MCH Core.............................................. .1.240<o:p></o:p>
- MCH Reference......................................AUT O<o:p></o:p>
- MCH DRAM Reference...........................AUTO<o:p></o:p>
- ICH I/O................................................. ...1.500<o:p></o:p>
DRAM<o:p></o:p>
- DRAM Voltage........................................2.1 00<o:p></o:p>
- DRAM Termination.................................AUTO<o :p></o:p>
- Channel A Reference..............................AUTO<o:p></o:p>
- Channel B Reference..............................AUTO<o:p></o:p>
<o:p></o:p>
DDR SETTINGS<o:p></o:p>
MCH Frequency Latch...............................400<o:p></o:p>
Sys. Mem. Multi. (SPD)..............................2D<o:p></o:p>
FSB:DRAM Divider.....................................1:1<o: p></o:p>
DRAM Frequency.......................................85 2MHz (Reading)<o:p></o:p>
CAS Latency Time (CL)...............................4<o:p></o:p>
RAS to CAS (tRCD)......................................4<o:p> </o:p>
RAS Precharge (tRP)...................................4<o:p></o:p>
Precharge Delay (tRAS)..............................12<o:p></o:p>
Advanced Timing Control <o:p></o:p>
- tRRD.............................................. ...........AUTO<o:p></o:p>
- tWTR.............................................. ..........AUTO<o:p></o:p>
- tWR............................................... ...........AUTO<o:p></o:p>
- tRFC.............................................. ...........AUTO<o:p></o:p>
- tRTP.............................................. ...........AUTO<o:p></o:p>
- Command Rate........................................AUTO


Thanks to all posters on this forum. You guys have helped me establish my first OC

[Jay8tsj]

Re: Help requested with stabilizing E8400 / P45-DS5 @ 3,87GHz

PS: How do I change the thread title to express the new status? I only seem able to change the post title, not that of the full thread.

[Psycho101]

Re: Help requested with stabilizing E8400 / P45-DS5 @ 3,87GHz

The forum doesn't support user thread title changes.

Not a bad OC, but Vcore seems a little high for the speed. Do you know the stepping of your E8400? If it's E0 then you can definitely get stable on much less voltage.

[Jay8tsj]

Re: Help requested with stabilizing E8400 / P45-DS5 @ 3,87GHz

Hey Psycho,

No, it's a C0 stepping. I kinda waited for the release of this CPU to built my system around it. I have understood that in general the E0's are better clockers? Guess that's the drawback of being an early adopter

Thanx for the advice. I will try to lower the VCore some, to see how it goes. For the rest, I was planning on seeing whether it will keep on running stable for a few weeks, before trying to raise my FSB some more. My current goal is to get it run stable @ 4GHz without having to raise the VCore close to 1.4V. Do you think the rest of the settings can stay as they are, or will they become the bottlenecks then? I know I will loosen my RAM timings to SPD defaults (5-5-5-18) before raising the FSB, to rule out that as an issue.

[Psycho101]

Re: Help requested with stabilizing E8400 / P45-DS5 @ 3,87GHz

As long as you adjust the System Memory Multiplier to make sure your RAM isn't being clocked past spec, you should be ok to procede from what you currently have set.

CPU termination may need raising as you go, up to a maximum of 1.38-1.40V depending on Vcore.

One little change I would make, which seems to be universal when overclocking dual cores is to lower MCH ref by one tick first, then try another tic down if you still have stability issues. Best way to do this id first to set CPU Term back to 1.2V, then set MCH Ref from auto to 0.740V. After adjusting MCH ref set CPU term back to 1.24V.

To put the effect of a lower MCH Ref into perspective, from my own experience, stock 0.760 @ 1.200V CPU Term failed prime for me right after starting the stress test. Lowering MCH Ref one tick got me 6 hours stable in Prime, and then an additional single bump in Vcore got 12 hours Large FFT's and now 24 hours of Blend. MCH ref is like magic, you can go from a knackered system to a great stable overclock in an instant.

E0 is generally a better overclocking stepping, however C0's aren't exactly poor either. I'd expect 3.6-3.9GHz from a C0 and 3.8-4.2GHz from an E0. this is all dependant on luck of the draw as far as individual chips go, plus how you're cooling it. If using water then 4.2GHz isn't out of the question on a C0, just expect to be using more voltage to get higher clocks than with an E0.