E6400 Overclock

T

Term-X

2[H]4U
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Apr 21, 2001
Messages
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Howdy,

I got myself a new set of RAM (OCZ PC2-6400 Platinum Rev 2; two kits of 2x1024MB) to replace my old Value Select 667 from Corsair. I was sitting at about 2.66GHz. Anyway, I have been tweaking things with my new pairs and I have been able to boot into Windows with the settings mentioned below. I ran memtest86 v3.4 for about 8 hours and no problems. 3DMark06 ran a few cycles and no apparent problems there either.

The problems occur when I run Prime 95 v25.4 Torture Test (Small FFTs). Usually within a minute or two, they both stop with errors (FATAL ERROR: Rounding was 0.5, expected less than 0.4). I tried increasing Vcore step by step about 3 notches or so but the same results (though I do see a trend where one core tends to fail faster than the other).

Below is my current hardware/settings:

CPU: E6400 (2.13GHz) @ 3,360 MHz
Heatsink: Artic Cooling Freezer 7 Pro
Case/Cooling: Antec P182 / 3 x 120 (S-Flex ducted towards GPU)
Motherboard: ASUS P5B (Vanilla)
RAM: OCZ PC2-6400 Platinum REV 2 (2 x OCZ2P800R22GK / 4GB)
PSU: Antec SmartPower 2.0 / 500-Watt

---------
BIOS Settings:

Vcore: 1.400v (BIOS) | CPU-Z / Everest: 1.336v / 1.325v
Multiplier: x 8.0
FSB: 420 MHz
VDIMM: 2.1v
RAM (1:1): 840 MHz | Timings: 4-4-4-15 (Sub: 4-35-10-10-10-11)
FSB Termination: Auto
CPU Extras Disabled (i.e. Vanderpool, Execute Disable Bit, Spread Spectrum, C1E Halt, CPUTM)
Memory Remap Feature Disabled
-----
Temperatures (Results From HWMonitor / CoreTemp):

"IDLE"

SYSTIN: 28c
CPUTIN: 49c
Core #0: 43c
Core #1: 39c
GPU Core: 49c

"LOAD"

SYSTIN: Max 29c
CPUTIN: Max 55c
Core #0: Max 53c
Core #1: Max 48c
GPU Core: Max 63c


So basically I am looking for some opinions as to whether or not I have hit my ceiling. A few things to keep in mind is that, as far as I am aware of, the P5B Vanilla has a maximum 2.1v setting for VDIMM (not that RAM seems to be the problem). Also, there doesn't seem to be any sort of voltage setting for the Northbridge (potentially my problem?). One thing that I also haven't explored in FSB Termination Voltage; I've tried to research it but everywhere I go to read, I seem to get a different answer. Some say it does not, some say it helps high overclocks. Some say to be careful and set it correctly (with no explanation on how the process works) and others say just go for the full 1.5v!


Any help would be appreciated
 
You could try loosening the RAM timings and dropping the CPU multi to see if you're hitting a FSB ceiling. Or maybe in loosening the RAM timings you'll find that it is a RAM problem. If you do the above and can get to a higher FSB, you might have reached the max that chip can do.

Tweak tweak tweak.
 
holli4pirating said:
You could try loosening the RAM timings and dropping the CPU multi to see if you're hitting a FSB ceiling. Or maybe in loosening the RAM timings you'll find that it is a RAM problem. If you do the above and can get to a higher FSB, you might have reached the max that chip can do.

Tweak tweak tweak.
Click to expand...

Good point. I dunno, I just figured that Memtest86 was the means to 100% prove memory stability but I guess that's the easy route. Reason why I am edgy now is, that despite my decent temps for air cooling, I am approaching that 1.35v Vcore "safe zone".
 
Well each voltage has it's own ceiling, so to speak. If your FSB is as high as you can get it and you don't want to up the volts anymore, then you are at your ceiling regardless of what the chip will do with more volts.
 
Yea I lowered the multiplier, kept everything else the same. Seems to be a problem with the 3.3 GHz frequency. Think I might try another notch of juice and if not, lower it some from there.
 
Term-X said:
Yea I lowered the multiplier, kept everything else the same. Seems to be a problem with the 3.3 GHz frequency. Think I might try another notch of juice and if not, lower it some from there.
Click to expand...

...that should drop the frequency; dropping the multi and leaving the FSB. Unless you meant you think it's a problem with the FSB, then that would make sense.
 
holli4pirating said:
...that should drop the frequency; dropping the multi and leaving the FSB. Unless you meant you think it's a problem with the FSB, then that would make sense.
Click to expand...

Yea I wanted to make sure FSB wasn't the problem, since it's always been in the back of my mind. This board does not provide the option to change Northbridge voltage.
 
Well, I told around with things a bit more, went a notch up in Vcore. It did not really stabilize much until I fiddled with FSB Termination Voltage. After adjusting it to 1.3-1.4v, seems to do alot more Small FFT tests before failing. One thing I have noticed, though, is that I may be affected by what is known as 'vdroop'. I know there is a trace mod out there so I am going to look into it and see if it helps.

(The 'vdroop' seems to drop me to 1.31v during load from 1.35v idle)
 
Dude, getting 3300mhz from a stock 2133mhz chip.....be happy. :D That's a nice overclock, well within the upper range for that chip. Especially for air cooling, lots of the 3.6 mega-hurtz overclocks you see are NOT stable for everyday gaming and what not.....lots of people lie. Plain and simple.

You have a GREAT overclock, enjoy it, getting 100mhz more is not going to adversely affect anything.
 
TheRapture said:
Dude, getting 3300mhz from a stock 2133mhz chip.....be happy. :D That's a nice overclock, well within the upper range for that chip. Especially for air cooling, lots of the 3.6 mega-hurtz overclocks you see are NOT stable for everyday gaming and what not.....lots of people lie. Plain and simple.

You have a GREAT overclock, enjoy it, getting 100mhz more is not going to adversely affect anything.
Click to expand...

No doubt but I wanted to be sure. I had to drop down to 3200 to be stable (8x400 FSB) so memory is running at par (I guess I could try to run memory higher by itself but I'm not sure it can hit DDR2-1000). Regardless, I think I'll be making another attempt at hitting 3.4-ish once I finish the vdroop mod. During load my vcore drops by 0.04-0.05.
 
Term-x, I had an E6400 before I got this 6750, and I also was pretty much maxed at 3200mhz...I could get 3300 out of it, but not stable at all.....I had to up the volts too much to make 3300 work even half ass, that temps went nuts....so 3200 it stayed at.
 
The 6400 is the chip I currently have, and so far I can only get it to boot at 3.1ghz unstable, with it stable at 2.9ghz. You've got a pretty good overclock there.
 
I got air cooling too my memory timings 4 4 4 12 and E6400 With the same Mobo you have, running stable at 3.2GHZ but the temps go arround 66C (Orthos) and 60(gaming COD 4), Voltage is 1.412.

I don't believe I will be putting more juice to this, Would you?
Jorge
 
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