Apple has released a 5500-6500 Extras disk image file (Thanks, Leonard Ornstein). Among other things it contains three bug-fix extensions:
5500/6500 ATA Update
5500/6500 Video Input Update
AudioTuneUp (presumably a new version)
Note especially that the ATA Update extension "improves performance when Virtual Memory is turned on in the Memory control panel." This seems to be a fix for the virtual memory slow down problem reported here previously. Check the Read Me file for more details on other fixes.
Power Macintosh 5500/225, 6500/225 and 6500/250 users, running Mac OS 7.6.1, who don't have these extensions, should install the 5500/6500 Extras Update. Current Power Macintosh 6500/225, 6500/250, 6500/275 and 6500/300 pre-installed with Mac OS 7.6.1, already include these 5500/6500 Updates. These users do not need to install this Update.