Hi @all,

I'm running an number of machines with Radeon Cards for MW crunching. One machine has two HD6950 and crunches 4 WUs at a time per GPU within max. 3 mins. Another machine has a HD5850 and a HD5970 and both cards seem to be able to do only 2 WUs per GPU within the 3min timeframe. If I try to run 3 WUs on these HD5xxx GPUs the execution time will go up extremely.

The number of shaders on the HD5xxx GPUs and their clocks are nearly the same as it is on the HD6xxx GPUs. Shouldn't it therefore be possible to run 3 or 4 WUs in parallel on such a HD5xxx GPU ?

best regards,
Rene

You are not actually crunching two WUs, in parallel, at a time. Your card works on one WU for a small time then pauses it while it works on another. The gain is that when the WU uses the CPU at the beginning and end of each WU, the GPU crunches another WU exclusively. There is little, if any, added benefit from crunching more than two WU per card. This is why your times per WU go up when you try.