I got a brand new (ok, refurbished) MBP 15" Retina (late 2013 hi-end model), installed clean OS X Yosemite and it's been running fine except I get graphical glitches. I don't know if these are OS based or if I should prepare myself for faulty GPU (GT 750M w/ 2GB VRAM). This sometimes happens randomly and switching between the desktops "cleans up" the mess. I had this happen quite often in Photoshop. Once I had it happen with quick view video playing (glitches in video) but checked in VLC if it's the file or not. I had one kernel panic when I switched to 3D Ray Tracing in After Effects and had bunch of other stuff open (I guess it could be not enough VRAM but I was just rotating extruded 3D text?). Restart fixed it. Premiere Pro is working flawlessly though. I have latest Nvidia CUDA driver installed. Then I tried playing X-Com (the new one ) with max details and max resolution, the computer handled it just fine. I'm kinda worried it might be faulty GPU... but would I be able to do screenshots of it if it was true (I'm no expert so idk). I have external 1080p display attached, I notice when switching apps I get this white blocky flickers in upper-right corner of menubar (using dark mode). These are the ones I caught today.