CPU upgrades are supposed to
be simple. Well, CPU upgrades in which you just pop out the old CPU and
install a new one are, anyway. If you change to a new kind of CPU that needs
a whole new motherboard, that's a different kettle of fish, but the CPU-installation
part of the upgrade still ought to be easy enough.
Both square "socket" type processors
and cartridge-encased "slot" type ones are meant to be no trouble to install.
People are nervous about it for no reason. It's not like changing your own
oil, it's more like just changing your own windscreen wipers. Right?
Well, usually, yes. But a few
recent developments have conspired to make many people's processor installation
experience exactly the sort of hardware-destroying nightmare that timid
people who get someone else to do all of this stuff for them are trying
to avoid.
If you're considering assembling
your own computer, or you're the bunny in your small business who's been
volunteered to swap new hardware into those old boxes around the office,
then you'll need to know a couple of things.
What's needed, to stop newcomers
from pulverising some of the newer CPU designs in the process of installing
them, is an illustrated step-by-step guide.
To find out why you may need
step by step instructions, though, you have to know about the new CPU types.
Form factors and fragility
Intel and AMD, who between them
practically own the PC processor market, both now mainly make single-chip
CPUs that don't need separate cache memory chips. Intel's current Celeron
and Pentium III CPUs are single-chip; so are AMD's Duron and current model
Athlons.
Because these CPUs don't need
extra chips, they don't need to be built into a big cartridge. Both manufacturers
are still making cartridge-type processors - Intel's Slot 1 and AMD's Slot
A, which use mechanically identical but electrically completely different
connectors - but they don't need to; there are no major components on the
circuit board in the cartridge but the CPU itself.
It's considerably cheaper to
make CPUs with no cartridge, so both Intel and AMD now prefer to sell the
socket versions. Intel's one is Socket 370, named for the number of pins;
AMD's is Socket 462, named for the same reason, and also known as Socket
A.
Socket 370 CPUs. On the right,
a 400MHz Celeron; on the left, a P-III. Note the difference in the size
of the raised portion - the "contact patch" - in the middle of the package.
The P-III, and Celerons from the 533A model upwards, use the small-patch
"flip chip" layout, which is significant, as we'll see.
Socket A CPUs, top view only
this time. Again, a small contact patch.
While Intel's still shifting
quite a lot of Slot 1 Pentium IIIs, a major upgrade these days will probably
see you using a socketed CPU.
Whatever kind of processor you've
got, you need to put some kind of CPU cooler on it. A "cooler" is a metal
heatsink with at least one fan on it. The fan's needed to keep the heatsink
size down, because modern desktop processors produce enough heat that passive
cooling with a fanless heatsink is only possible if the heatsink is really
humungous.
You can use a merely big heatsink,
with no fan attached to it, if you've got a case designed for maximum air
flow and, probably, an extra case fan to help out the one in the power supply.
But purely passive cooling is very challenging. Apple's elegant little Power
Mac G4 Cube has no fan, and uses nothing but convection for cooling. But
it goes into standby mode automatically if you block its vents by putting
something on top of it, and it will probably still crash after a few minutes
if the obstruction stays there.
So you need a CPU cooler.
And herein lies the problem.
CPU coolers for slot-type processors
aren't too tricky a proposition. The old, fully enclosed Single Edge Contact
Cartridge (SECC) processor design completely encases the CPU circuit board,
with a "thermal plate" on one side onto which you clip the cooler. All Slot
A Athlons are SECC, as are various older model Pentium II and III.
