(Relatively) Cheap Thrills: AMD K6-III+ CPU Upgrade

[Leon Goldstein]

I have a Compaq Presario 5151 with an AMD K6-2 350 mHz.
I used this little desktop tower for over three years with Libranet
1.9.1.  With newer releases using KDE 3.x, performance was very
demanding of patience:  KDE 3.1 took almost a minute to load.  I have 
256 MB of RAM onboard.

So, I decided to take a chance with an upgrade to a K6-III.  I bought a
K6-III+ 450 mHz CPU from
http://www.upgradeability.com/K6plus/index.htm?source=AdWords1
after detailed correspondence with the owner.

The K6-III+ has some instructions that make it almost the equivalent of a
slow Duron.

I installed the K6-III+ and it works very nicely indeed.  KDE 3.1
(Libranet 2.8.1) now loads in about 23 seconds - a bit sluggish by
contemporary standards but acceptable.  The system reports a K6-III with
256 kb cache memory.  The big onboard L2 cache is the main reason this
CPU performs so well.  I am using the original passive heatsink at the
moment, and there is no overheating problem so far.  The K6-III+ uses a
2.0 V core voltage vice the original 2.2 V.  I may try overclocking when
I modify a short heatsink/fan for updraft.  On the Presario the heatsink
abutts the power supply, and a shroud ducts air from the heatsink into
the PS vents.  There is little clearance between the CPU and the PS, so
a short heatsink/fan is needed.  Also, because typical heatsink fans
blow downwards, I would probably have an airflow problem that might
cause the PS to overheat.  (Perenthetic question:  if heat rises, why do 
heartsink fans blow air
downwards?)

I obtained a heavy copper heatsink/fan from the same source (Evercool)
and I need to fabricate a gasket in order to reverse the fan so its hub
has some clearance from the top of the fins.

If anyone has an old Compaq laptop with a K6-2 CPU, this looks
like a relatively inexpensive way to get a substantial performance
boost.  Issues are ability to select the correct core voltage and a BIOS
that recognizes the K6-III's internal L2 cache.  My Compaq 5151 needed a
BIOS flash upgrade for K6-III compatibility, but I had already done that
when I first got it.  I have a "sofpaq" CD I got from Compaq several 
years ago, so
if someone needs a BIOS upgrade (and can't get it from the Compaq/HP 
website)
I may have it.

And why bother?  The Presario 5151 is very quite and unobtrusive sitting
on my desk.  I now have a nice quiet desktop that can handle KDE3.x and
other RAM/CPU resource hogs.   Adding the new heatsink/fan will probably
make it as noisy as any other box, but I'll report on that at the
appropriate time.  Adding a UDMA/100 IDE interface card and a WD Jumbo
HD with 8 MB cache will make this old. modestly performing box very usable.

-- 
Leon A. Goldstein

Powered by Libranet 2.8 Debian Linux
System G2