I'm getting a high CPU usage as well.
It's not a recent update problem. I'm using 4.6.691, a build that's worked perfectly up until recently, now it's coming up with the same problem.
Shutting down all scans does nothing (ie. "Stop On-access Protection") ashServ.exe still hogs processor usage, is stuck on "High" priority, and refuses to let me change it's priority. The only way to fix it, besides restarting the computer, is killing the process.
My hard drives are also set at DMA, not PIO, before anyone asks. Plain, simple IDE drives, none of this fancy SATA stuff LOL.
Any ideas so far?
'Shady