The screen is fine, no flickering or tearing etc. I don't get blackouts either. But one thing thats bugging me is it makes an audible droning sound all the time. I tried changed fan speeds with smcFanControl but that doesn't change the droning sound. It's a similar noise to the noise my Time Capsule makes when it's getting accessed. Only my iMac is making the noise all the time? Is this the dreaded Seagate noise? It does have that drive If I copy files to the hard drive I can hear it being accessed but it isn't that loud, yet this droning noise just won't go?