Plus another minus this card vs my old nvidia: my computer didn't shut down with this card. I hear that HDD is stopped, but video is on and I need to power off the computer hard. I have not this problem when I shutting down computer from windows or when using nvidia card.
tried that already, it had no effect on the problem. Somewhere I've read AGP aperture should be equal to the amount of video memory for fglrx, but my mainboard only allows up to 256M (512M on the 3850 card).
Does your mainboard allow changing the voltage for your AGP card?
I had to up it to 1.65V on my Abit Av8 with H.I.S. RadeonHD "Turbo Edition" 3850 AGP before 3d apps would run stable in either Windows or Linux. 2D apps and windows itself caused no problems at all at any voltage.(This required going to the voltages page in the BIOS and changing from "auto" to "manual" after which I could set the memory, CPU core and AGP voltages by hand.)
At 1.55V or lower, the "VPU Recover" interrupts would happen about once every 5 minutes while 3D benchmarking or gaming in Windows XP.