Help with E8500

[ilan2212]

Hey all!
This is my first overclock , on my newish system.
My problem is this:
I'm trying to get 4Ghz but I cant seem to it stable. (~422x9.5)
I dont know at which Vcc to max out - Im currently on 1.4 in bios , 1.328 in CPU-Z , is that where I should stop or can I go higher?
I havent changed anything besides FSB and DDR timings(lower).
I have options that I haven't changed that might be affecting this:
FSB overvoltage and MCH overvoltage.
In my current state , prime95 gets an error about 20 minutes and the temps max at ~70C.
My spec:
E8500
Gigabyte P35-DS3 (rev 2.1)
Corsair XMS2
OCZ Vendetta 2
Case W/3 Fans.

 

[Andrius]

At 422MHz FSB you are also overclocking your RAM. Since you didn't specify what type of Corsair RAM you are using make sure you try loose timings of 5-5-5-15 also, and if neccessary raise RAM voltages to specified levels (~2.1V for DHX C4 modules).

You will likely need to raise (G)MCH and FSB voltages a bit as well.
First reduce the multiplier from 9.5 to 7.5 (that puts you close to stock CPU frequency) and check if it's stable (I needed to raise both settings one notch for 400MHz).

After you get that configuration stable raise CPU Vcore and CPU multiplyer.

EDIT: 1.4V CPU voltage is already above Intel's VID range for an E8500 but as long as CPU-Z reports Vcore under 1.3625V under load I think you are safe. See : http://processorfinder.intel.com/details.aspx?sSpec=SLAPK
As always the final decision is up to you as it is your money and hardware you are playing with.

 

[Shadow703793]

^+1. You need to increase voltages and relax timing.

For 45nm: Absolute MAX is 1.4v
For 65nm: Absolute MAX is 1.5v

VID is NOT the same as MAX voltage.

 

[Andrius]

@Shadow703793
AFAIK VID is a reference value for the voltage regulators on the motherboard. CPU voltage (or Vcore) is the voltage the chip is getting and should be as close as possible to but not over VID (that's where Vdrop and Vdroop come into play) at all times for stable "stock" operation.

I would not put Vcore outside Intel's specified VID range for 24/7 operation, but that's just me.

 

[ilan2212]

RAM timings are already loosened , so I will try lowering the multiplier and checking if the prob was with the other voltages.
BTW , Im currently running 410 FSB stable , with low timings , with all voltages at default except Vcc.
EDIT: why are the (G)MCH and FSB voltages use large (in my opinion) voltage incerements of 0.1?

 

[pcgamer12]

Wow 70C is terrible, don't OC with stock cooler.

 

[ilan2212]

Something very strange happened - suddenly the CPU temp jumped by about 10-15 C after I changed the multiplier from 9.5 to 7.5 (FSB 410).
It was working well on 9.5 with 1.4 v , now I changed it back to stock settings and its still very hot!
What the hell happened?

 

[shadowthor]

No idea, is the fan turning at the max speed?

 

[Andrius]

Are you using CoreTemp?
CoreTemp has some issues with 45nm chips.

Try CPUID HW Monitor and RealTemp.
RealTemp needs to be calibrated.

If all 3 show the same general temperature try remounting your heatsink (it uses pushpins and could have come loose).

 

[Shadow703793]

^+1 for RealTemp.

@Shadow703793
AFAIK VID is a reference value for the voltage regulators on the motherboard. CPU voltage (or Vcore) is the voltage the chip is getting and should be as close as possible to but not over VID (that's where Vdrop and Vdroop come into play) at all times for stable "stock" operation.

I would not put Vcore outside Intel's specified VID range for 24/7 operation, but that's just me.

I should have been more clear. The voltages I listed earlier are the ABSOLUTE MAX you should put in to those chips. Those voltages are the point of no return, meaning physical damage can occur at those voltages. Sorry for the confusion .

 

[Andrius]

@Shadow703793
I agree with the max values you posted (at least for the 65nm, the 45nm might be a bit high for my taste but I don't really know as it's not my chip and I can't make that decision for myself).

I just wanted to clear up the meaning of VID since you posted :

VID is NOT the same as MAX voltage.

I would assume Intel's VID range from ProcessorSpecFinder is a good guideline for max volatges (at least for 24/7 operation) but personaly I wouldn't raise the core voltage over 110% default Vcore.

 

[Shadow703793]

^It is a good guide idea not to exceed max VID, but knowing Intel those are usually conservative (except for a few CPUs). I still say keep the voltages below max VID but if doing some real hard core OCing you will need to go beyond those voltages.

 

[ilan2212]

I remounted the heatsink , so the temps are OK.
I still don't understand if the value intel posted is the value set in the BIOS or the one shown by CPU-Z and other programs inside windows.

 

[ilan2212]

Voltages on CPU-Z under stress show 1.312v while on idle show 1.344v , which are both under the maximum recommended voltage given by intel , yet in the BIOS , I went a bit above it , so the question remains: which voltage
doest intel refer to - BIOS or the...other one?

 

[iluvgillgill]

i think the real voltage in windows is what it really OPERATES ON. if you can understand that you have thew answer.