🚀 go-pugleaf

In article <RFowler.288@kelvin.jpl.nasa.gov> RFowler@kelvin.jpl.nasa.gov (Robert A. Fowler) writes:
>In comp.ibm.pc.hardware there is a thread about weather the 486DX uses a 1x 
>or a 2x clock.  I (perhaps mistakenly) said it used a 2x clock, (all of the 
>motherbords I've seen had a 2x occilator) could some one with a real data 
>book clarify?

The 386 uses a 2x clock, whereas the 486 uses a 1x clock.
A 2x clock has the advantage of delivering a perfectly symmetrical
1x clock after halving. A 1x clock needs better clock circuitry to
make sure it is symmetrical.

A 2x clock makes it difficult to drive a 50Mhz cpu (using 100Mhz oscillator)
without interference with the FM radio frequencies. (Maybe that's why
nobody sells 50Mhz 386's)

I can tell you from experience that listening to a distant radio station
at frequency 99.9Mhz is difficult when parked in the lot in front of a
major PC vendor's development lab. And they are not even using
100Mhz oscillators (but the 25 and 50Mhz ones have overtones).

Paul.