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[CPU] E8500 Core 2 Duo OC troubles

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  • CPUs
  • Overclocking
Last response: in Overclocking
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August 27, 2008 7:34:40 PM

Hi,

I just got a E8500 3.16MHz (SLAPK / Q817A342 batch) yesterday to replace an E6750 and I try to do a lazy 20% O.C. to reach 400FSB (3,8MHz).
I started by leaving all stock in the BIOS and was able to reach 340-350-365 then 385MHz… all tested with Prime 95 (v25.6), Orthos and Everest (v4.5Ult). Then I raised the CPUVoltage to 1.2685-1.2720+…. but it crash quickly on any test inlc. BSOD sometimes. I am not that much of an O.C.er but I did in the past with my E6750 and was so smooth.

List of my parts :
-Windows Ult. Eng. x86 (32bits)*
-Asus P5K Rev. A2 BIOS 1103
-4Gb (2x2kit) Patriot Memory 800MHz 4-4-4-12 @ 2.2volt (EPP profile)*3326Mb seen as it’s 32 bits OS.
-Asus EAH 4870 512Mb
-2 x 7200.11 500Gb 32Mb HD from Seagate
-550VX Corsair P.S.U.
// RAM tested with Memtest 2.01 many times and CPU sensors tested with Real Temp. 2.70 too.

Also I noticed that the CPU fan is the way not as good as the previous one… getting a temp. above 15C higher than the one on my E6750. Runing in a dust free P182 with 4 fans at medium speed. Temp. room is 24-25C stable.

If anyone could help on this I would appreciate it 

More about : cpu e8500 core duo troubles

August 28, 2008 3:59:18 PM

More tests... I realize that my VCore is dropping EVERY time I try a "stress test" application like Prime95 or Orthos.
Example:
Idle: 1.192V Load: 1.148-1.152
Checked ith CPUz 1.47

Is it normal?
So I am back on stock settings since I removed the battery to reset everything...

Thanks...C-A
August 29, 2008 6:43:57 PM

***The new CPU coolers from Intel (the small Alu. ones) are the worst ever! Don't even thrust em if you don't have a well ventilated case. Simply get anything else :) 
I do have a P182 with Scythes @ 49CFM Imagine what it would be without(!)

Ok... now on a brand P5Q-E and having a Zalman 9500AT at hand.... it goes at least quite better with a good -13 to 15C at idle.

The guy at intel told me that the heat an delse was normal... well. Everything is stable stock speed as well.

I need help in here to get your O.C. Vcore and MCH numbers to help out a bit. I'm only planning a 20% O.C.

thanks in advance!!
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August 30, 2008 6:43:25 PM

charlesalexandre said:
***The new CPU coolers from Intel (the small Alu. ones) are the worst ever! Don't even thrust em if you don't have a well ventilated case. Simply get anything else :) 
I do have a P182 with Scythes @ 49CFM Imagine what it would be without(!)

Ok... now on a brand P5Q-E and having a Zalman 9500AT at hand.... it goes at least quite better with a good -13 to 15C at idle.

The guy at intel told me that the heat an delse was normal... well. Everything is stable stock speed as well.

I need help in here to get your O.C. Vcore and MCH numbers to help out a bit. I'm only planning a 20% O.C.

thanks in advance!!


You may just need more voltage. Intel states the max voltage for these chips is 1.3625. On my E8400 this is contradicted by a the label stating 1.25V max (does the E8500 label say this too?). The voltage you want to keep under the stated max is your load voltage. Don't be too concerned about what you set it at in BIOS because as you will see, this isn't the actual voltage once you are in Windows. I wouldn't be too concerned with your MCH voltage yet. You should not need to increase that for a minor OC. I am at a 33% OC and I left mine untouched. The only voltage in bios I have increased is vcore.

To put it in perspective, here's my OC #'s
E8400 @ 4005 mhz (445FSB x 9.0 mult)
BIOS vcore setting 1.375v
CPU-Z Core Voltage under full load (Prime95 small fft) = 1.296v
Right now @ full load, core 0 temp = 52C, core 1 temp 54C
August 30, 2008 8:51:29 PM

Thanks Ryan...

You're right it should not require much except raising the Vcore.

I've seen online peoples talking about @ voltage from 1.225 to 1.275 depending on motherboard brand ( Asus is more hungry on O.C.) Probably that my P5K was not able to keep the 45mn CPU OK even if they run at a lower voltage... but the P5Q-E with updated Bios run it like cake.

I'm testing the Vcore act., as said I just plan to keep that at 400FSB... There is way too much options in this BIOS (which is not that bad after all :p ) so if anyone have suggestions it's more than welcome.
My room is quite hot today with 29C ambient and I am still at 45C at full load OC (3800MHz) all on [auto].(!) I expect to get it around 40C or less at full load with the CNPS9500AT @ 2000RPM with a room at23-24C.

thanks,

CA



August 30, 2008 9:56:01 PM

Ryan is mistaken regarding voltages. Check out the Intel datasheet for the e8400 for the correct details.
September 2, 2008 5:18:12 PM

So far,

Got My new P5Q-E and my E8500 at 3,8GHz on air cooled. (Zalman CNPS 9500AT standard speed).

The only thing IS ... the P5Q-E BIOS is full of options (maybe too much for small clockers) and the ram (Patriot CAS4 DDR2-800MHz) is having a high latency... 65ns.
Working on it :) 
!