Project 560
This is how the SL2W8 looks without the case. The CPU
is in the center and the L2 caches are on either ends. The SL2W8 is an OEM CPU. The only
real difference between an OEM CPU and a retail one is the OEM unit doesn't come with a
heatsink, which is good because removing the factory heatsink is not easy as Project 527
showed. This was the main reason I wanted my second PII-300 to be an OEM unit. I didn't
want to go thought the trouble of removing the factory heatsink. I'm lazy. :-)
To make the jump from 527 to 560Mhz, I decided to
remove the case and and fill in the gap between the L2 cache and the Global Win heatsink.
Since I have a super high quality CPU that booted into Windows at 560Mhz with just a stock
heatsink with no cooling of the L2 cache, I figured cooling the L2 cache should be all
that is required to run stable at 560Mhz.
Ripping off the case really isn't that hard. The unit
is held together by 4 pins on the outer corners. All you need is a screw driver and allot
of guts! To find out step by step how to remove the case, go to HardOCP. They have a
really nice article on it. I'll let Kyle explain how it's done, so if you blow it up, you
can blame him. :)
The advantage of removing the case is that you can
better cool the L2 cache of the PII. The stock unit's L2 cache does not come into contact
with the heatsink. By removing the case, I was able to put in 2 metal spacers to fill in
the gap between the L2 cache and the heatsink (You can use coins if you don't have access
to a machine shop).
The L2 cache was the thing that was preventing this CPU
from running stable at 560Mhz. I have tried 560 with the L2 cache turned off and it ran
without problems, even doing a whole hour of Quake 2 timedemos! However once I turn back
on the L2 cache, it would lock up after 15 to 20 minutes of heavy use. It ran Windows and
business aps fine however.
While I had the CPU all apart I decided to take a
closer look at the L2 cache to see what quality of L2 this unit came with. For a long time
I thought it had 5ns cache because that's what the Cupid info told me. However I have
since found that the only real way of telling what kind of L2 cache you have is by
opening up the case and looking at the L2 itself. With 5ns cache, it would be very hard to
do 504Mhz much less 527 or 560, so I was really wondering how I could do it if my L2 was
really 5ns.
 As you can see from the pic on the left,
my SL2W8 comes with Toshiba 4.4ns, 225Mhz cache and not the 5ns cache that allot of
PII-300s came with. This explains why the unit ran flawlessly at 504 and 527Mhz. When
overclocking a PII, it's the CPU's L2 cache that is holding it back, not the CPU itself.
225Mhz cache is the fastest cache Intel uses for the PIIs. It is rated to run in a
PII-450, since the L2 cache in a PII runs at half the speed of the CPU (450Mhz / 2 =
225Mhz).
By running the CPU at 560Mhz, the L2 cache would be
running at 280Mhz. Quite allot faster than the 225Mhz the cache is supposed to run at. All
the more reason to keep it cool! In case you're wondering, the CPU in Project 527 uses the
same 225Mhz L2 cache as the SL2W8. So how come the Project 527 won't do 560 and the SL2W8
will? I simply lucked out in getting a REALLY GOOD CPU! If your SL2W8 can't do 560 by
using the cooling system I ran, then it's because your CPU just can't do it. Only 40% of
SL2W8 can do 504Mhz. I'm sure the number that can do 560 is much lower.
Now you might be wondering how a PII-300 ended up with
L2 cache used in a PII-450? I don't have the answer to this one. Some say that these
PII-300 were really PII-450 that Intel just remarked and sold because they had too many of
them. What ever the reason, I saved myself some major bucks by getting a SL2W8 instead of
a *real* PII-450.
Go To Cooling The CPU
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