OC'ing P5K-Pro - limited to 350Mhz FSB?

[CE_Mikemonster]

Hello everyone,

 

I've been trying to OC my e8500 Core 2 Duo and every time I set the FSB to over 350mhz it fails to post. I've googled all afternoon but can't find anything like this.

 

350mhz is all happy, 351mhz will not post. Temps are all ok, 32c at idle.

 

I have a feeling there could be an obvious answer, but this is doing my head in!

 

Thanks in advance, Mike

[Axion]

Make sure you are not overclocking your RAM, as you increase the FSB you will need to decrease the frequency of your RAM to either it's original rated speed or just below.

 

Other things like disabling C1E Support, Max CPUID and Intel Speed Step will help.

Edited January 3, 2009 by Axion

[CE_Mikemonster]

Thanks mate. When I turn the ram freq down to min (667Mhz or close) it POST's, then shows the 'Windows' loading bar for a second, then reboots.

 

So the RAM Freq did make a difference, but I fail to see what difference is between 350Mhz and 351Mhz fsb lol

 

At the moment i'm on 350Mhz with RAM at 993 or near, working fine?!

 

Core 2 Duo E8500 (3.16Ghz stock speed)

P5K-Pro

PC-8500 Corsair Dominator RAM (5-5-5-15, 1066Mhz, 2.1V)

Vista-64

[Axion]

That would suggest to me that something other than your memory is causing instabilty.

 

PM Sent.:smilewink:

[rapid]

Hi, I have the same CPU and im leaving mine at 3.80GHz.

what rating is your Ram rated at?

if your FSB is not in relation to your ram speed the pc will fail to load.

[CE_Mikemonster]

I see, cheers Rapid, i'll have a proper look now whilst gf has something on the Eurovision song contest on.

 

I'm running a divider of 1:1 for FSB:RAM, as far as i'm aware.

 

------------------------------------------------------------------------------------------------

Having looked in BIOS, Working Settings are:

 

FSB Freq: 350MHz

DRAM Freq: 933Mhz

That's with the CPU at 3.34Ghz speed, total FSB of 1411MHz

 

 

And Non-Working settings are:

 

FSB Freq: 360MHz

DRAM Freq: 959MHz

 

As for RAM ratio's, despite understanding the concept I can't see any BIOS options related to them. The nearest thing to it I can think of is the 'CPU Ratio Setting', which is at 09.5 (My CPU has a 9.5x Multiplier as standard)

 

Edited January 3, 2009 by CE_Mikemonster

[CE_Mikemonster]

note: Fixed, methinks.

 

Updated BIOS and #wallahh# it works!

Cheers for advice/time, thanks a lot for the file as well Axion.

 

At the mo OC'd at 3.42GHz with stable temps ~50C

 

Might even buy a non-stock HSF!

 

Regards all, MM

[CE_Mikemonster]

Brilliant. I'm not bumping this, it's just the problem has re-occured, only this time it seems the FSB ceiling is 380MHz.

 

380= ok

381+= no POST

 

 

I've sorted the RAM ratio as well, cheers rapid.

 

 

EDIT: All sorted now, it was a low NB voltage as well as the CPU voltages needing to be raised a little bit. Ty

Edited January 6, 2009 by CE_Mikemonster
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