Sapphire HD7990 QuadFireX Review

Our test system uses the ultra high end Asus Rampage IV Extreme. We installed both HD7990's in adjacent slots on the motherboard. There were no problems initially however the fans on the top card quickly began to work overtime when we started the testing. The backplate on these cards does get quite hot under load.

In this configuration, the three fans on the top HD7990 were directly sucking in warm air radiated from the back plate on the lower card. The bottom card was working as expected, but the top card was running at around 93c under load. We needed to space the two cards out.

We moved the bottom card down to the third slot on the ASUS motherboard, sadly however the supplied Crossfire connector didn't extend far enough. We have a few extra long length Crossfire connectors in our labs however, so we swapped over. You can buy these 10cm extra long connectors for around £5 from Ebay, if you need one.

Crossfire X worked fine and the upper card was able to intake cool air directly over the heatsinks thanks to the increased spacing. The fans didn't have to work so hard either and the temperatures dropped.

If you want to run two of these cards in CrossfireX it is worth looking into the configuration of your motherboard and if specific slots needed will run at x16 or x8 when two cards are paired up.

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