I just bought and installed an EAH5770 CuCore yesterday but am seeing some strange behavior when I try to overclock even the tiniest bit. I have two LCD displays, the main on DVI and a secondary on the VGA connector. Things are stable and beautiful at stock settings running Win7 64 and Cat 10.2. Whenever I attempt to adjust the core or memory clocks by any amount (up or down) however, I see graphics corruption in my secondary display. I used to enjoy the same setup with a HD4870 and had no problems with a moderate overclock. I'm wondering if I just happened to get a dud 5770 or if there's something else going on. I used both the Catalyst control center and ASUS SmartDoc to overclock and even tried bumping the vcore up a touch without success. Anything other than default GPU or video memory clock rates immediate produces problems. I wouldn't have thought anything odd if this happened above a minor overclock ceiling but when it happens even with a tiny underclock, I get suspicious. I've reinstalled the official Cat 10.2 a few times now. Any suggestions or should I just RMA?