I installed Mac OS 8.6 two weeks ago (yes I had it) and it disabled my 512K backside cache on my Rev. A iMac. The installation had wasn't without problems, so I figured the backside cache deal was a fluke and went back to 8.5.1 until Apple Publically released 8.6. Well I downloaded and installed 8.6 today, and my machine is running very smoothly. But it take 30 secs longer to start, 50% longer than I am used to, and guess what? No backside cache. Do any of you have this problem?

Ok you got b9 working all right . Please see to reinstall b9 or you can zap the pram that seems to be making things difficult with the rev b as well as some BWG3 those guard pages are killers as far as safety goes but they tend to slow down system with low memory.