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From: pjgtech@cix.compulink.co.uk ("Peter Gagg")
Subject: Re: Celeron 300A - no more overclocking possible?
Message-ID: <F34yHu.B6M@cix.compulink.co.uk>
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References: <01be1923$2bac3b50$c05481c1@dgj>
Date: Sat, 28 Nov 1998 14:20:18 GMT
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In article <01be1923$2bac3b50$c05481c1@dgj>, dgj(@)mfltd.co.uk (D. 
Gwyn Jones) wrote:

> Mark R. <Sparks@spam_this.mailroom.com> wrote:
> > I had to bump my core voltage up to 2.2v to get my C300A stable
> > at 450... 
> 
> Guys, please fill me in here...
> If the C300A Celeron (128K cache, right?) is so easy to overclock 
> to 450
> (with a 100MHz motherboard, right?), is there any point at all in 
> getting a
> C333A since that costs 30 percent more in the UK?

No, don't do it. Just buy a 300A (yes, the "A" denotes the cpu has 
128kb on cpu cache) I have a 333A and despite several unsuccessful 
attempts it will only reliably o/c to 375 (5 x 75) I have had it 
running at 415 (5 x 83) but not reliably, 500 (5 x 100) did not work 
at all.

The 333A is locked at a multiplier of 5. So if you try to overclock 
it, you have to mulitiply the busspeed by 5 which is pushing the cpu 
and the busspeed to its limits before you even start o/c'ing? So the 
only options are as above 375, 415, or 500. 375 appears to work fine, 
415 works but not reliably and 500 not at all, as you are trying to 
push the cpu that little bit too far?

The 300A on the other hand, is locked at a multiplier of 4.5 which is 
much more user friendly. The options are now 300 (66 x 4.5) 337 (4.5 
x 75) 375 (4.5 x 83) 450 (4.5 x 100) or even 504 (4.5 x 112) Most 
people attain 450, some manage 504 (though how reliable they are at 
that speed is debateable?)

> And what's all this about 2.0v and 2.2v core voltage? What does 
> that refer
> to and how do you set it?

Your m/b sets the core voltage, (the voltage used to power the cpu) 
most newer bx m/bs have a core voltage around 2v. But when you try to 
o/c a cpu, it sometimes needs more voltage to attain the extra speed, 
so people try raising the voltage until the cpu performs reliably 
(2.2v appears to be a reliable setting to try?).

Most m/b's allow you to change the core voltage via jumper settings 
on the m/b or via a *softbios* menu (eg:- the Abit BH6 & BX6 m/b's)
 
> If the C300A really is as good as it sounds, I would quite happily 
> go for
> one and just overclock it at times when I need it, like playing 
GPL.

You can do this easily if you have a m/b that allows softbios  
settings, you merely boot up the pc, go into the bios, and set the 
cpu/voltage settings, then let the pc carry on booting, and away you 
go.

But, if you have a m/b that requires jumper setting to be changed, 
you have to take off the case, alter the m/b jumpers, start the pc, 
etc, etc, this is too much hassle for most people unles you are gonna 
leave the pc o/c'ed all the time.

Also bear in mind the o/c'ing (especially increasing core voltages) 
results in increase heat build up, and you need to check the internal 
case temperatures or buy extra fans to cool the m/b & cpu.

There *are* risks to o/c'ing, you *can* damage your cpu! Its up to 
you?

8-)

*Peter*   #:-)
