Low Performance on GPUs
First, Calculate and Verify your PPD to see if there really is a problem. If you're running on a lower performance CPU, disable CPU folding, as this can often reduce the effectiveness of GPU folding.
Low Performance on Headless GPU
In some cases, Headless GPUs on Windows 7 or XP will be in a "disabled" state in Catalyst Control Center (for AMD devices). Adding a Dummy Plug or powered KVM will resolve this by showing the GPU a connected device.
Devices Not Present
Select "Configure" in the [email protected] client and check the "Slots" tab. If necessary, add GPU slots for additional devices that are not yet present.
Work Unit hangs at 99.9%
If you're overclocking your GPUs, remove the overclock, or gently underclock. In most cases the 99.9% hang occurs due to a driver crash or other GPU error. Stock clocks, or a slight underclock, seem to resolve this in most cases without affecting PPD.