[gentoo-user] Re: Overclocking CPU causes segmentation fault

[Nikos Chantziaras]

On 22/01/13 13:14, Nilesh Govindrajan wrote:
> On Tuesday 22 January 2013 03:13:01 PM IST, Nikos Chantziaras wrote:
>> On 22/01/13 09:41, Nilesh Govindrajan wrote:
>>> So I have this old E2180 processor and no money as of now to buy a new
>>> rig :P
>>> I'm trying to overclock my CPU using BIOS host clock control and
>>> everything is fine at 2.6 Ghz up to bootloader.
>>>
>>> Kernel segfaults. Any idea why? I'm running pf-kernel 3.7.2 and it
>>> doesn't work with vanilla kernel either.
>>>
>>> Intel MCE is disabled in kernel configuration.
>>
>> When you raise the "host clock", which is the FSB, you are also
>> raising the frequency of your RAM.  So make sure you select a lower
>> FSB:DRAM ratio in your BIOS.  To begin with, set it to 1:1.
>>
>> Also, if you only have the stock CPU cooler that came with it, you
>> won't be able to actually get a stable overclock.  Your CPU's stock
>> frequency is 2GHz.  Without a better cooler, you might get it to 2.2
>> or 2.3 maybe.  But 2.6?  That's pretty optimistic.  I don't think
>> it'll work in the long run, unless you happen to have picked a good
>> chip that can be overclocked without raising the VCore.
>>
>> But first, solve the RAM problem by lowering the FSB:DRAM ratio.
>>
>>
>
> I don't get even 2.1 with the stock cooler. Temperature easily goes
> above 75-80 (spec say high temp is 86) on the prime95 test. Quite easy
> to cook it considering that I'm a Gentoo user :D
> Not really worth that. Thanks for replies.

It really worth trying *lowering* VCore instead of raising it. If your 
chip happens to be very good and deal with this without causing 
instabilities, this will result in a big drop of temperatures.  I did 
this on a C2D CPU in the past.  I lowered VCore and raised FSB.  I ended 
up with a good performance boost *and* lower temperatures. 
Unfortunately, not all chips behave the same.  It's hit and miss.