Building a second rig, and currently testing with a single 290x. I get an error when I try to start up cgminer


 [2013-12-17 20:02:33] Started cgminer 3.7.2
 [2013-12-17 20:02:33] Probing for an alive pool
 [2013-12-17 20:02:35] Pool 0 difficulty changed to 512
 [2013-12-17 20:02:37] Network diff set to 111
 [2013-12-17 20:02:37] Error -4: Enqueueing kernel onto command queue. (clEnqueueNDRangeKernel)
 [2013-12-17 20:02:37] GPU 0 failure, disabling!

I'm running on 1 x Corsair 4GB, and google linked me to some forum discussions about increasing RAM to 8GB. I replaced with 2x4 gskills and it worked. I thought a lot of people mine with just 4gb, so is this Corsair stick bad?