For laughs I've been running a 486dx/33 (intel) at
66mhz in a dell box.
The only mod if the heat sink is a moose I had and its attached to the
chip using a BEo filled thermal epoxy. Runs cool and it's solid.
486dx33 at
66 MHz ? Well, I don't want to be picky, but wouldn't
this result in 66 MHz CPU bus ? Sounds a bit off for 486 Boards.
ISA not PCI. The
bus is still cpuclock /n and n in that case is 8.
Well, I wasn't talking about the I/O bus (as ISA or PCI should
be considered), but rather about the CPU bus - and if you overclock
an (non multiplieable) basic 486DX CPU, the only way is to raise bus
speed - and 66 MHz is way out of Spec for all 486es I know - regulary
only the AMD Parts are speced for 40 or the old Intel DX50 (was quite
a beast - just _way_ expensive, and rarely seen - I guess the yield
was just to low to promote it).
I've tried that in a socket5 Mb I have using a
486dx2/50 at 100mhz, seems
fine after three months. The cooling is not big a problem.
Jep, the most notable
CPU is still the AMD 5x86 (486dx4/133 with
extended cache) - I have them running at 4x40 MHz == 160 MHz without
any problem - only for high load apps the cooling must be presen,
a Linux (web) server can even run without a fan.
I have about 8 of them running
here at work including one as a NT3.51
server all at 133mhz. Very good machines!
Jep. And running at 40 MHz bus speed still comperable to any P100
I found it
hard to run NMOS 6502 on more than 1.3 times their nominal speed.
The 8085s and
z80s would run that fast but things like propagation times
don't shrink so the access times and all do not scale well. For example
take a 4mhz z80 to 6mhz and you better have memory that is faster than
what would be needed first at glance. Same thing pushing 8085H-2 (6mhz,
to 8mhz).
True. But for the 6502 even more the CPU itself was often the hardest
part to tweak. Geting fast Memorys wasn't that problem - the CPU itself
starts to malfunction, possibly the propagation times within the CPU
where already stressed.
Gruss
H.
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Ich denke, also bin ich, also gut
HRK