The Athlon, the Pepsi to Intel's
Coke, is definitely not a CPU to glance over. First
the obvious comparisons: the Athlon is just plain WAY cheaper
per clock speed than a Pentium III. I mean WAY cheaper.
The Athlons also overclock quite well (more on this in a minute),
and are neck in neck with a Coppermine PIII performance wise.
The Athlons run on a simulated 200 MHz FSB. Simulated?
Well the actual speed is 100 MHz, but the CPU can access the
system bus twice per clock cycle, on the down side and the
up side, so in effect the bus runs at 200 MHz. The Athlons
use the Slot A, which is physically identical but electrically
incompatible with Slot 1. This means they need an entirely
new set of motherboards to run them, and only now are there
any good ones coming out. See the chart below for good
Athlon motherboards. Also, overclocking the Athlons
is a bit different. The same raising FSB method still
applies, so do the same cooling rules, but you also have another
option, that of a Golden Fingers Device. A Golden Fingers
Device (or GFD as I will refer to it) is a little PCB with
some dip switches on it that plugs onto a little set of connects
on the top right of the Athlon's PCB. The GFD (of which
there are a variety of types out there to choose from that
cost around $50) allows you to not only change the voltage
to the CPU (if your mobo can't), but it also allows you to
CHANGE the CPU's multiplier.
What's that? The multiplier?
Yep, AMD doesn't multiplier lock their CPU's yet (YET...),
so using the GFD you can change it to whatever you darn well
please. This means you can raise the CPU to high clock
speeds while keeping a 100 MHz FSB and therefore not needing
to worry about expensive RAM. However, the Athlon's
have one problem, their L2 cache. You see, unlike the
PIII's and Celerons, the Athlon's cache is NOT on die (in
the core itself) it's two chips off to the side on the PCB.
Therefore the L2 cache does NOT run as fast as the processor,
instead the Athlon uses a cache divisor. For instance
on Athlon chips up to the 700 (I believe), the Athlon's cache
has a divisor of 1/2 so it runs at 350 mhz. From 700
to the 850 MHz CPU's, the cache runs at 2/5 the core speed,
and anything above 850 the cache runs at 1/3 the core speed.
What does this mean to you? Well the Coppermine's on
die L2 cache gives it a definite performance advantage in
some applications, and in others the Athlon can still win
due to the CPU's better FPU performance. However when
overclocking, the cache becomes a major factor. Say
you buy a Athlon 650 chip. It has the cache running
at 1/2 speed. This means that anything above 750-800mhz
or so, the cache will start holding you back because it can't
run that fast even though the CPU core could. The obvious
solution? Change the cache divisor from 1/2 to 2/5 right?
Well yes, but the problem is that currently the only way to
do that is to re-solder some tiny resistors on the back of
the Athlon. NOT FUN. There ARE some places that
will do it for you if you send them your CPU for about $50,
but either way it's a raw deal.
The Abit KA7 motherboard
has a experimental bios that will let you set the cache divisor, but I
tried it on my KA7 and it just plain didn't work. There is also a
program out there by H. Oda (the guy who did SoftFSB, you can find more
info on his page)
that can change the divisor, but I haven't tried it yet, you can also download
it from Tweak Files. Overall
the Athlon is a very strong contender due to it's excellent performance
per clock speed ratio, and it's very low price. Now that we are seeing
some good overclocking motherboards for the Athlon, the future looks even
better. However due to it's cache limitations, it is still being
held back from it's full potential.
A Personal Note About the Upcoming AMD Thunderbird:
The AMD Thunderbird is like a Athlon on steroids, with more
L2 cache which is now ON-DIE (no more divisors) and some will
have copper interconnects in the CPU die. It will be
using a new Socket A format, which will require a new set
of motherboards. It will be making it's debut this Monday
and if you ask me, as long as the motherboards are up to snuff,
the Thunderbird is going to HORRIFICALLY OWN. This is
just me speculating, but I think it's going to kick a
grown Coppermine to grandma's house and back. However
it is unknown exactly how it will perform, or how well it
will overclock. Just keep your eyes open (let the "you're
bashing Intel" flames begin...).
Well, now that we have gone over the basics of
the various CPU's out there that are good for overclocking,
now it's time to find a motherboard for that shiny new processor
you just bought. I'm not going to go over every single
motherboard out there because that would REALLY piss off my
carpal tunnel syndrome, so instead here is a handy chart.
This shows the kind of CPU, along with the websites of GOOD
overclocking motherboard manufacturers for that CPU.
This is NOT a complete list, these are just suggestions to
get the ball rolling. Before you buy a motherboard,
RESEARCH. Read reviews on it, look up prices on places
and overall do NOT rush into a decision. And remember,
stick to brand names motherboards! Here is a chart of
possibilities to start you off with:
||Noteworthy Motherboard Manufacturer's Websites
provide plenty of options in choosing a motherboard.
Abit and Soyo in particular are leading the pack in overclocking
motherboards, but others are definitely making headway.
Also, if you chose to use a PPGA or FC-PGA processor with
a Slot 1 motherboard, you will need a Slocket adapter.
Abit and Iwill in particular make very good Slocket adapters
for about $20.
Okay, now that we've decided
which CPU and motherboard to buy, it's time for one final
piece of hardware which ultimately will spell the do or die
for overclocking. Yes, it's time to COOL down that burning
hunk of processor love with a heatsink/fan.
Choosing A Heatsink/Fan:
For the sake of brevity from now on I will refer to a heatsink/fan combo
as a HSF. The HSF is what (obviously) cools down your CPU and since
heat is the main enemy of overclocking, the HSF should be an item you pay
special attention to. I'll say it right now, a GOOD HSF is going
to cost between $40 and $50 usually. There are of course exceptions,
but expect to pay the most to get the best, and when it comes to the HSF
for overclocking, do NOT skimp! Now then, choosing a HSF will depend
on what processor you have, or more specifically, how it's mounted.
Whether it's a Socket 370, Slot 1, or Slot A. There are a wide variety
of HSF's for each type of mounting but the same basic rules apply to each.
I will not talk about how to mount the HSF here because honestly each and
every one is a bit different. They should come with instructions
though, so don't worry. One important thing, ALWAYS ALWAYS use thermal
paste between the CPU and the heatsink. Most good HSF's come with
a some thermal paste, or you can buy it at a computer store. Instructions
for applying it are below in the cooling section. ALWAYS use it though,
otherwise you are doing more harm than good.
Like motherboards, there are a couple of notable HSF companies that
you should definitely look in to. First off is Global
Win, Global Win makes HSF's for every CPU imaginable and most of them
are damn good. Combine that with their wide availability and good
prices, and you have a good solid choice. Go to their website and
find the best HSF for you're mounting configuration, then use a site like
Pricewatch to find places that
carry it for the best price. Next up are the infamous Alpha's.
Long the all out performance leaders in HSF's, the Alpha's are big, bad,
and expensive. If you want the ABSOLUTE best HSF money can buy, invest
in an Alpha. However, along with that performance comes two downsides,
first off they're expensive, around $50 sometimes, and second: Some of
the better Alpha's are HUGE. As in cover the first one or two ram
slots huge. Take my advice, MEASURE how much space you have between
your CPU and ram slots before you buy one of these honkers. Oh and
one more thing, some of the larger Global Win and Alpha coolers can get
quite loud. The Alpha's are often renamed and sold by sites under
different names. Check www.3dfxcool.com,
for some Alpha goodness.