Help OC'ing e8500

S

Samury

Limp Gawd
Joined
Feb 7, 2006
Messages
199
****Updated with current values****
I had a previous thread here but I thought I should start fresh with a new one and more info. My comp is the one in my sig, and here is how I set everything up in Gigabyte's Intelligent Tweaker:

Robust Graphics Booster [Auto]
CPU multiplier 9.5

Host Clock Control Enabled
FSB Frequency 444
PCI Express 100
CIA2 Disabled

CPU Clock Drive 800 mV
PCX Clock Drive 900 mV
CPU Clock Skew 0 ps
MCH Clock Skew 0 ps

-----DRAM-----
Performance Enhance Turbo
Extreme Mem Profile Auto
GMCH Latch 400
Memory multiplier 2.6d
Memory Frequency 1066
CAS Latency 5
tRCD 5
tRP 5
tRAS 15
-----Advanced Timing-----
tRRD 4 [Auto]
tWTR 4 [Auto]
tWR 8 [Auto]
tRFC 68 [Auto]
tRTP 4 [Auto]
Com Rate 0 [Auto]
Static tRead 10
Trd2rd 8 [Auto]
Twr2wr 8 [Auto]
Twr2rd 7 [Auto]
Trd2wr 9 [Auto]

CPU vcore 1.3975
CPU termination 1.3
CPU PLL 1.75 (this will go down, but I'm not at that comp now)
CPU Reference 0.785

MCH core 1.2
MCH reference 0.70
MCH/DRAM reference 0.9 [Auto]
ICH i/o 1.5
ICH core 1.1

DRAM voltage 2.1
DRAM termination 0.9 [1.05] For some reason even though these are set to 1.05
Channel A reference 0.9 [1.05] they never change from 0.9.
Channel B reference 0.9 [1.05]

Sorry for the formatting. Temp is 39-40 standard and maxed out at 60 running Prime 95, air cooled with a Scythe Zipang.

This is on Win7 64-bit, btw. Any suggestions for changes to make it stable in Blend?

Thanks for any help.
 
Well, this is odd. Running memtest86, it failed almost immediately in 1.35, but passed 1.34. Any ideas?

Even odder, I ran memtest+, v. 2.21 (IIRC) and it too passed, no problems.

Note that this was tested at default voltages, not OC'd. So any ideas?
 
You could try playing with your MCH ref, but do that last after you find some settings that you like. You shouldn't need a 1.3v mch. I don't even need that for my Quad with a higher fsb. Try 1.26 or 1.28. Vtt seems low. Definetly try your ram out at 1.9 and turn off that performance enhance untill you get things stable.
 
Under auto for RAM Hardware Monitor gives 2.08V for the DDR, whereas if I set it to 1.9 I get 1.9, so I'm going to leave it on auto for now.

Edit - now set to 2.08 with the rest at 1.04. Hardware Monitor now gives 2.05 for DDR. Maybe I should just go 2.10 and say "screw you fuchsia!"
 
BababooeyHTJ said:
You could try playing with your MCH ref, but do that last after you find some settings that you like. You shouldn't need a 1.3v mch. I don't even need that for my Quad with a higher fsb. Try 1.26 or 1.28. Vtt seems low. Definetly try your ram out at 1.9 and turn off that performance enhance untill you get things stable.
Click to expand...

When you say "VTT seems low" do you mean the CPU Termination, or something else, because when I tried running it 1.22 it was a no-go (but maybe it just needs more juice?). Since I've read that VTT can mean several things I'm curious if it's one of the other settings on a Gigabyte board.
 
Reboost Graphic Controller- Turbo
Cpu Clock Ratio - 9
Fine Cpu Clock Ratio- +0.5

Cpu Host Control- Enabled
Cpu Host Frequency- 430
Pci Express Freq - 100
C.I.A.2- Disabled

Leave Advanced Clock Control Alone

Performance Enhance- Extreme
Extreme Memory Profile- Auto
MCH Frequency Latch- 333
System Mem Multi - 2.40B

Dram Timings Table- Manual (Make sure your rams rated Timings are correct)

Load Line Calibration- Enabled
Cpu Vcore - 1.375 (Since your last attempt was 1.35V)
Cpu Termination- 1.28V
Cpu PLL- 1.50V
Cpu Ref- 0.810V

MCH Core- 1.28V
MCH Ref- 0.89


Those settings are what you need to put into the bios, Also, those settings will have your ram at 1032, So you can just up the fsb up til its 1066, Lower the multi to 9.0 if you see the chip goes too high for you and or voltage you feel safe going into.

I have done the ref values for you already, Which in most cases will make some overclocks stable, Stock values are fine for low overclocks, but for decent runs, its basically needed, but some get away with leaving them at stock/normal.

One thing you can do is do 1.4V, and just keep stress testing and lowering the voltage until its stable and that is what you need for your overclock, meaning, if your using Prime95, Turn it up to 1.4V, Run blend for 4 hours, It passes, go back into bios, lower it to 1.39V, and retest until unstable. Or if your using the amazing ibt, Just run 5-10 runs at full stress and repeat like i said.

Let me know if you have any questions by posting on here or pming me :cool:
 
That didn't work.

It definitely didn't like the Extreme memory setting. So I'll try again with the other settings.

Edit - tried again with your suggestions, but Memory set to Turbo, and it wouldn't post. Any ideas where to go from here?
 
You need to slowly work your way up, until you hit instability without changing advanced settings.

Is your machine 24/7 stable at stock settings?
 
The VTT is the FSB Termination Voltage. Despite popular belief your VTT shouldn't be too far off from your VCC (core voltage). You might want to bump up your Dram voltage to 1.9 or 2.0 without a DMM there is no way to be sure that your ram is even being fed 1.8v.

Disable the memory performance options untill you get everything stable then tweek from there. I never had luck with those options myself and tighter timings will net you more bandwith and lower latency anyways. Start off with 5-5-5-15 55trfc and pl10 with your memory options and just try to get your fsb stable, then you can play with memory timings.

Don't mess with the clock gen options unless you absolutely have to.
 
MisterSparkle said:
You need to slowly work your way up, until you hit instability without changing advanced settings.

Is your machine 24/7 stable at stock settings?
Click to expand...

I've tried slow. I've tried fast. Both with varying results, but nothing quite perfect.

As to your question, I'm finding that out now - I don't think I ran the Blend test under stock settings. Otherwise, it runs fine 24/7, but so do the OCs that failed stress tests, so that's not saying much.

UPDATE - Blend ran stably for 6 or 7 hours with stock settings, except for the memory which was at 2.1V (though the rest are 0.9, even after I specified 1.05).

One thing that I came across while resetting everything: should I try setting HPET to 64 bit in the BIOS since I'm using Win 7-64?
 
HPET is for Windows Vista and above, and I believe you can have it on 64-bit if you are running a 64-bit CPU (which you are) and a 64-bit windows (which you are too).

The first key with diagnosing an overclock, is to go back to the roots. It's very hard to find a definitive answer to an overclocking problem when there are multiple variables that could be influencing the results.
 
I'm trying a new tack: I leave everything except the RAM timing on Auto and adjust the FSB speed upwards. Then I use Easy Tune to see what value is set and I'll tweak from there.

Currently I'm at 400 MHz with a Vcore of 1.35, Term 1.2, PLL 1.65, Ref .76, MCH 1.2, Ref .76. So far Blend has been stable for an hour. If it runs through the night I'm considering whether to jump to 444 and see what Auto sets to, or to try to tweak from here. My one concern is that it may try to bump the vcore to 1.4 or higher, which I don't want, so maybe setting that at 1.39x would be better.

Does this sound like a sensible plan?

Edit - RAM is set to 2.1V and Static tRead at 10 (Auto lowered it to 6 from 8 when I upped the voltage).

Update - Blend test was stable for 14 hours with a max temp of 58 on both cores.
 
Tried a 444 FSB: I had to manually set the vcore to 1.3975 - for my own peace of mind, then set the CPU ref to .785 and the MCH ref to .700 after Auto caused Windows to crash on launch.

Auto set CPU Termination to 1.3 and PLL to 1.75.

Now to try Prime 95.
 
You do NOT need more than 1.56 PLL for your clocks/voltages, tops. Thats one of the more dangerous settings on your board. Your VTT (FSBterm) is a little low, I don't keep it too far from my vcore. Your MCH is a little low as well. you should only need 1.26 or 1.28. With these settings if you can get prime to fail in about 45 minutes to an hour you should be able to stabilize your clocks by just tweeking your CPU GTLs. My e8400 liked them at 645% (percentage of VTT), this setting will vary makes sure to tweek it last, but before tweeking your memory.
 
BababooeyHTJ said:
You do NOT need more than 1.56 PLL for your clocks/voltages, tops. Thats one of the more dangerous settings on your board. Your VTT (FSBterm) is a little low, I don't keep it too far from my vcore. Your MCH is a little low as well. you should only need 1.26 or 1.28. With these settings if you can get prime to fail in about 45 minutes to an hour you should be able to stabilize your clocks by just tweeking your CPU GTLs. My e8400 liked them at 645% (percentage of VTT), this setting will vary makes sure to tweek it last, but before tweeking your memory.
Click to expand...

Thanks, I'll lower the PLL as soon as I get home. I'm thinking 1.35 for the VTT.

From my OP, which are the GTLs? I haven't seen anything in the BIOS that has % as a value.
 
It is the cpu refrence and there should be 2 settings for it, I just set them both the same. You normally want to set them somewhere inbetween 0.80v ond 1.00v, my wolfdale was set to 0.85ish (it's set differently on my board) and the optimal GTL will be different based on VCC, VTT, and your FSB so it's just trial and error really. Don't go crazy with the GTLs, Ive just found that if you can get to the point where your failing prime small ffts after about an hour you can usually stabilize by just play ing with your GTLs. Good luck
 
Thanks for the advice. I lowered the PLL to 1.5 and upped the VTT to 1.32, and that let me get to 422 at 1.35 and run Blend for over 10 hours without a glitch. On to 444.
 
Update: I'm stable at 433 with a 1.3625 vcore, 1.32 VTT, 1.5 PLL, .815 CPUref, and MCH core of 1.28, MCH ref .70 (.68 didn't work).

But I can't seem to find the sweet spot for 444. I've tried upping the vcore several notches, plus the VTT to 1.34, the PLL to 1.57 (my only next option), the CPU ref, and the MCH Core up, and the ref down to 0.68.

But no matter what I try, it always destabilizes. Any ideas what I've missed? I've tried multiple combinations of the above, but always come up flat. Maybe there's a combination I'm missing.
 
Many thanks to all. I'm Blend-stable at 430 and I think I'll quite while I'm ahead.

Final voltages are:

vcore 1.3625
VTT 1.32
PLL 1.5
CPUref .815
MCH Core 1.26
MCH Ref .70

Hopefully I'll boost it more later, but I'm happy with this, since it surpassed my goal of 4 GHz.
 
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