[Any empty reply that I sent to the list just now was due to finger trouble; hit Ctrl-Enter rather than Ctrl-End out of habit :-/ Sorry about that.]
> Is this a chip replacement that you install? Or how difficult is it to > do this upgrade? That particular model was designed to replace a 486 chip that sat in a Socket 2 or Socket 3 motherboard; most of those designs used ZIF (Zero Insertion Force) sockets, so have a small lever that you pull upward to release the existing chip, drop the new one in the socket, and push the lever back down to hold it in place. Very simple upgrade if you can get to the existing chip -- some cases could hide the processor in stupid places under support bars etc. though. I think some motherboards that were compatible with this didn't have the ZIF-type sockets, instead just a standard chunk of plastic with holes. In those cases, the existing CPU would be pried out of the socket (ISTR a tool was supplied with some OverDrive chips for the purpose) and the new one (very carefully!) pushed into place. I can't remember offhand if the Socket 2/3 spec made the ZIF socket mandatory I'm afraid. Best bet is to take a look at the board -- if there's a small lever to the side of the CPU socket, it's a 'drop-it-in-and-go' job. Incidentally, some OverDrives were designed to sit in a special 'OverDrive socket' alongside the existing 486 chip; these sockets were blue instead of the CPU's white socket. It's been a long time since I've had to think about this so the details are fuzzy; some creative Googling will probably turn up more complete/definitive answers. Last time I used these chips was the P90 version (or maybe P100) on a bunch of 486SX/25s; we could have sworn some of the cheaper machines ended up feeling slower (probably the rest of the system dragging the processor down; slow RAM, ISA bus...). Regards, Ben A L Jemmett. (http://web.ukonline.co.uk/ben.jemmett/, http://www.deltasoft.com/)
