I have two Radeon HD 7950's in crossfire, a reference design HIS model that I bought near launch day, and a Gigabyte Windforce model i bought last winter. The issue that I am having is with the core clock on the Windforce card. When I put it in the GPU 2 slot (below the HIS card), the core clock constantly fluctuates under load between about 900 mhz (below the base clock) and 1100 mhz (the clock I have set in afterburner), however, when I have the windforce card in the GPU 1 slot and the HIS card in the GPU 2 slot, this does not happen, and the clocks on both cards stay constant at their set values. The reason that I want to switch the cards is because I am getting very high temperatures (~89 degrees) on the windforce card in game when it is the top card, and I have heard that the reference cooler performs better directly above another card in crossfire.
Is this an issue of using mismatched cards, or is something else amiss?
Is this an issue of using mismatched cards, or is something else amiss?