12 Apr
2008
12 Apr
'08
9:42 p.m.
Sridhar Ayengar wrote:
Curtis H. Wilbar Jr. wrote:
I tended not to get more than about 20% out of 286s, 386s, 486s, Pentiums,
PIIIs, etc... I've generally used 20% as a rule. 33% was the 2.4 Prescott
P4 at 3.0GHz... I considered that pretty good. It might have gone farther,
but I only have DDR333 in that system. Approaching 3GHz, it would get
picky about startup... process was, hit power button, count to 5, press
reset
button and it would come up fine.... however the first minute or two would
be touch and go... 10-20% of the time if you logged into quick it could
blue screen and reboot. After that first couple of minutes it was
stable....
I now have it at 2.8 and we'll see how startup and stability are.
I'm still quite surprised you got a 50% overclock. I have an upgrade
(little PCB with the surface mount Am586 on it, and a cpu pin header
for the cpu socket... along with a few jumpers/etc. I might have to
try it at 50mhz fsb... I'd think that would make a pretty quick 486
based system.
-- Curt
Cameron Kaiser wrote:
My guess is he is running the front side bus at 50mhz (as genuine
DX50 systems do) vs the 33mhz fsb that the Am5x86-133 is designed for
(33.3*4 = 133, 50*4 = 200).
Exactly.
I *love*
486DX-50 machines. I've had some success in the past
installing Am5x86-133 chips in these machines running at 200MHz.
What did you change on the board to get the 200MHz speed? I have a
-133 here that I'd love to try that on.
I wouldn't have imagined that part would
handle a 50% overclock. I
have not found many processors in my limited overclocking experience
that exceed 20% overclock w/o fiddling with "excessive" cooling,
increasing core voltage, etc.
Considering that the Am5x86 ran reasonably reliably with no heatsink
at all, running with a minimal heatsink and fan, it's not that big of
a deal.
I have been running a 2.4 Prescott P4 at
3.0Ghz... but once in a
while until it is warmed up it will blue screen and reboot.... so
I've backed it off to 2.8 to see how it goes.... I'm wary of jacking
the core voltage... (although it isn't a northwood so I don't have to
worry about SNDS). I may inherit some 2.8GHZ Prescott P4s with
800mhz fsb (vs the 2.4/533 I have now OC'd to 2.8)... so may go with
one of those :-) (plus they have HT (woo... moan...).
Back then, processors weren't so high-strung from the factory.
Peace... Sridhar