As long as it fits the case I don't see a problem. Also the size of the card depends on the manufacturer, not the card itself. Personally I'd recommend the R9 390 if your PSU can run it, however I'd recommend having a good fan in the front of the case for either card. If you don't have a good fan in the front just buy and hook up a CoolerMaster JetFlo (they are also available with LED colors which look very nice).