Subject: Overclocking CPU: some facts
Date: Fri May 26 05:45:40 1995

The subj. have been discussed for a long time and sometimes is still
discussed in the FIDO echoes of ex-USSR. I'll try to summarize the
knowledge about subj., because I'm sick of receiving postings with
discoveries of well-known things:

1. To make a CPU work at higher frequency you should just set proper
jumpers on your motherboard (RTFM, or look at writings on the mother-
board). If the motherboard hasn't the jumpers or it's max. freq. is
too low, you'll have to fuck your brain with hardware hacking.

2. If you want to speed up DX4/100 in 50MHz motherboard, try to change
internal frequency multiplier from 3 to 2 and set frequency to 50Mhz
(you must have a jumper that sets the multiplier)

3. Don't forget to cool your CPU, or it won't be cool :).
Even speeded up DX/33 works better with a cooler.

4. You shouldn't be afraid about "what will happen with my little
sweet DX2 if I make it work much harder" ;))) because almost all
DX2's are produced as 80Mhz ones and then marked as 80,66,or 50 Mhz
according to testing results. Generally, I haven't heard about any
case of CPU damage due to speeding it up.

5. Your other hardware like multy i/o boards, video card etc. may
fail to work at a new speed, because now ISA bus is timed by CPU clock.
The failure leads to unstable work of a machine. Try to set higher
ISA bus frequency divider if this happens.
If your cross 33Mhz barrier don't forget to insert 1 wait state to VLB
timing (set the jumper).

SY, Yar

---