Stuck with an officially un-upgradable Mac? You may have to take the unofficial path, as long as you're willing to take your warranty in your own hands (assuming that your Mac is even under warranty anymore). First, you can try a logic board swap. Many Mac models with sliding logic boards (especially older Performas and all-in-one LC models) can be quickly upgraded to a faster Mac. These upgrades don't always work, but pre-PowerPC Performas have been known to run with PowerPC 603e processors.

In other cases, the logic board upgrade may be more difficult but doable, especially if you buy an upgrade kit and get a professional to install it. So, where do you find these boards? Try Shreve Systems, NEXCOMP, or MilagroMac for starters. Used Mac Web sites or auction sites are also good bets.

If you're really nuts, you can try something called clock chipping, a trick Macheads perform to replace the existing quartz oscillating clock on the logic board with a faster clock. You can find the upgrades from MicroMac and others. You may get a decent speed boost but be aware that clock-chipping a processor too high can introduce errors, affecting stability. You may want to consider RAM and cache RAM upgrades instead of clock-chipping.