FastMac has announced G4 processor upgrades for slot-loading G3 iMacs for US$199.95. The company is offering a 550 MHz G4 processor upgrade that also upgrades the backside cache from 512 kilobytes (512k) to one megabyte (1MB) for 350 MHz, 400 MHz , 450 MHz, and 500 MHz slot-loading G3 iMacs, except for Dalmation and Flower Power models.
The upgrade requires your iMacis logic board, which is sent to the company for upgrading. That process takes from 7-9 days.
For an extra $30, the company will send you an advance logic board that you can use to replace your existing one immediately, eliminating any delays, and allowing you to send FastMac your logic board after you have done the upgrade.
The company said in a statement that it can offer 3-4 times the performance of your original iMac, and that it is compatible with Mac OS 9 and Mac OS X. In addition, FastMac is offering a one year warranty.
You can find more information on the upgrade, including information on the advance exchange program, at FastMacis site.