Level editor causing Graphics Drivers Issues?

[plutomaniac]

No problem with the double post, don't worry about it. In case you have another BSOD I suggest you play Tomb Raider again with the 7850 working card and

a) If it does there's something wrong with your operating system (very unlikely in this case).
b) If it doesn't it's safe to say the R9 270 is defective on a hardware level and RMA is needed (should have warranty).

To avoid the RMA right away maybe you could try the R9 270 on another PC with the same drivers & game but I suspect it's a hardware defect. It can happen, just RMA it and you'll get a free replacement.

Do you have any other background programs related to the graphics card like fraps, game boosters etc? Unlikely that's a problem since it would also cause it at the 7850 and not just the R9 270. Just covering all bases.