Example: Normally 486-33, 66, 100 or 133 mhz CPU clk/4 = 8.25 mhz. Most ISA cards will take 20-40% more speed, so change the clk/4 to clk/3 = 11mhz. The 40, 80 or 120 mhz AMD's have it good: 40/4 = 10 mhz, not quite so big a jump but more stable. No ISA card I know of will get past 12-13 mhz reliably so consider it the limit. 386-25 clk/3 = 8.33 mhz, clk/2 = 12.5 mhz; right to the edge (but there may be a 2.5 setting). Thus the 286/386/486 crowd (especially the all ISA slot machines) will be very happy as the overall system can run 5-30% faster, verifiable by general peppiness, some improved frame rates on video clips, and some diag progs test scores (TroubleShooter and CheckIt come to mind). Remember to change back if any sign of errors or crashes result.
8088 PC's are a harder nut.
Sometimes a jumper sets the bus speed but usually there's a clock crystal hardwired in. Some crystals were socketed and you can swap in a slightly faster one easily. Look for the square silver box(s) on your MB the size of a thumb nail. The speed is printed on them (14.xx or 8.xx or 33.3333, etc.). Keep the total increases to 20% for stability. Where to get them? Electronics stores and from old set scan video cards. EGA's and early VGA's had up to 5! There were faster 8088 chips out there too. Note: You with VL-Bus and early PCI have to be careful as the jumpers on the MBoard could modify their bus clock even more. The ISA bus may work fine but the fast VL-Bus will freak, so consult your manuals, if you have 'em. You may have to set the fast bus for a slower CPU (as mine did) to get it all to happen. Still this tweek can be quite a boost for no cash.
