So, this happened to me, and I have to share it because it seems to have SOLVED THIS PROBLEM and I don't really understand why. I'm going to share everything that happened today so that maybe someone can shed some light, and maybe it'll help someone else.
TLDR: I was booting to blue screen, but running a Verify Disk and a Repair Disk twice (in that order) using either target mode or an external enclosure fixed my graphics card problem. Has this phenomenon been reported before, or can anyone else try it out and report back? Just what the heck is going on?
I have 15" early 2011 macbook. I upgraded the ram myself, and this past december I installed a new SSD and put a clean version of Mavericks on it. In mid-January I experienced this graphics cards issue. It started with a screen shift. Two days later I got the 3d/interlaced effect. I did a hard shutdown and rebooted to a blue screen. I took it to an authorized repair center, they replaced the motherboard a week later, and my computer had been good until this very morning.
This morning, the screen shift happened again. I was able to shutdown safely. Rebooted, launched chrome and the screen shifted again almost immediately. Repeated safe reboot again, this time backed up some files first, launched Chrome again: Shift. So I'm noticing a pattern here. I removed all strain on the graphics card (disconnected external monitor), booted, and this time launched Safari. No problem. Did a little more research and learned about GFX CardStatus, so I downloaded that and launched it. My plan at this point was to see if launching Chrome would cause another shift, but before I did that I tried changing GFX CardStatus from Dynamic Switching to indiscreet. I instantly got 3d/interlaced effect, was forced to hard shutdown, and got a blue screen upon boot.
Fast forward to this evening. I was planning to take my Macbook back to the repair center tomorrow, but wanted to put the original ssd back in so I could use the new ssd on a nearby Mac Pro and continue working (external boot). I put the old drive in the macbook, tried a boot. I fully expected it to go to blue screen. Instead, it got stuck on a grey screen with no apple logo. Tried a NVRAM reset, no change. So I'm figuring that right now it looks like the old drive needs a disk verification and repair. I booted in target mode and used the mac pro and the following in disk utility, and IN THIS ORDER (this seems important somehow): Repair Disk, Verify Disk, Verify Disk again (was an accident but I decided to wait it out). Ejected target drive, rebooted macbook, walked away for a moment.
When I came back I again expect a blue screen, but I instead found the desktop waiting for me. What?? Okay weird, what the ****. I took advantage of the moment to go ahead and download GFX CardStatus for this particular drive. Switched from dynamic to indiscreet with no problems, I bounced between indiscreet and discreet several times with no issues. So I put GFX SS back on dynamic, and launched Chrome. Then I spammed facebook tabs, about 20 or so, and then started closing them quickly. I actually saw GFX SS switch to discreet, and the screen immediately shifted. Now, if you're thinking that 20 facebook tabs shouldn't force into discreet mode, I'd agree with you and you'll see that this situation changes shortly.
Now I quit out of chrome, and the screen UNSHIFTED as it switched back to indiscreet. This was new to me and I hadn't read about it elsewhere. At this point I did something that forced another 3d/interlaced effect and a blue screen on reboot, though I don't remember exactly what... so I figured okay, let's try another disk repair.
Target mode again, this time I did a Verify Disk and Repair Disk, one time each, in that order. rebooted, and I got the blue screen. So I went back to target mode, and did the exact same thing I did before. Repair Disk, Verify Disk twice. Reboot, BACK TO DESKTOP.
Now I am really intrigued. I bounce the GFX SS mode several more times with no problems. Launched chrome and spammed and ridiculous amount of tabs: now no problems. Huh? I made sure to launch some 1080p videos, still no problems. So then I downloaded some graphic stress tests (http://unigine.com/products/heaven/ the quickest thing I found with a fast google) and ran the successfully. I did everything in discreet mode, indiscreet mode, and with dynamic mode. I could not get the graphics problems to return. I tried really hard because I can't take the macbook back to the repair center if there is nothing visibly wrong.
At this point, I decided to put the new SSD back in, but I followed the Repair-Verify-Verifiy process using an external drive enclosure first. Put the SSD back into the macbook, booted, had to do a NVRAM reset, and boom desktop. I did all of the same testing: found it **** near impossible to force an automatic switch to discreet mode in Chrome, but found switching worked fine with the graphics stress test, and I just could not get the card to fail again.
So now I am back home, writing this with the macbook with a total "graphics card failure" just this morning, using the external monitor. I can't test any more because the problem hasn't returned -- and I'm not saying it's not going to.
TLDR: I was booting to blue screen, but running a Verify Disk and a Repair Disk twice (in that order) using either target mode or an external enclosure fixed my graphics card problem. Has this phenomenon been reported before, or can anyone else try it out and report back? Just what the heck is going on? Am I just crazy? I don't know, but maybe this will help some people.