I realised I made some passing references to
overclocking
in my last post about mainboards without explaining
myself.
Both Intel and AMD use the same method for
setting
the speed of the processor. The processor has a built in multiplier which
is
locked (it can be altered on AMD processors, but certainly on the XP
Athlons it
involves some rather delicate surgery using conductive fluid, and of course
doesn’t do your warranty an awful lot of good).
P4s and current Athlons are rated for speed based
on a
Front Side Bus (FSB) speed of 133MHz. The FSB is the bus which links
processor
with main memory. AGP and PCI bus speeds are usually set as a multiple (or
fraction) of FSB speeds. The easy way to overclocking is to increase the
FSB
speed using a suitable motherboard. Most modern motherboards allow the FSB
and
the AGP and PCI bus speeds to be set within the bios.
If only it were that simple!
You’ll need memory that is capable of
running
at higher speeds. Fortunately Corsair (www.corsairmicro.com)
(part of the same group as Micron) have just released 2700 DDR Ram which
has a
design speed of 166MHz (they already produce 2400 with a design speed of
150MHz). Overclockers (www.overclockers.co.uk)
expect to have it in stock in a couple of days or so. It already comes with
a
heat sink attached.
As you will be running the processor faster than
its
design speed you’ll need to cool it properly. I’ve had a lot of
success with the Alpha range of aftermarket heat sinks. Diehard
overclockers
actually use Freon based liquid cooling systems which actually cool the
processor to below 0 while it is running under load!
You’ll also need to increase the core
voltage
the CPU runs at – be careful with this one, set it too high and
you’ll fry your processor!
Once you’ve set the new parameters in the
bios,
you’ll need to run a torture test on your PC to make sure that
everything
is as it should be. Running 3DMark2001 (http://www.madonion.com/)
continuously for a couple of hours is good enough. If the PC locks up or
the
textures start ripping then you’ve pushed it too far. There are
others
available but things have moved on a bit since I built my current PC so
I’m a bit out of touch. I’ll post a list once I get up to
date.
It’s important to use a monitoring program
to
keep an idea on the temperature/fan operation/voltages etc. Motherboard
Monitor
is a freeware alternative to the programs which ship with the boards (http://mbm.livewiredev.com/). It has
some useful features which allow you to force a shutdown if certain
parameters
are reached.
What’s the point? Take the example of the
Athlon XP 1500+. It has a design speed of 1.33 GHz (10 x 133). If you go
the
whole hog and get the bus up to 166MHz then it will run at 1.66GHz –
the
same speed as the XP 2000+ but at a cost of 110 quid rather than 270
–
plus it will actually run faster due to higher memory
bandwidth.
Is it worth it? I actually enjoy the process of
getting there, so I suppose it is J
Tim.