AMD Radeon 6870 HD Died

Until recently, I owned the Radeon 6870 HD video card. However, it died under mysterious circumstances, and I want to insure that I don't happen across this again.

I was playing my game (FFXIV:Heavensward) - my computer was under a prolonged high load (5+ hours). Immediately on exiting a dungeon is when my machine crashed and through some troubleshooting, was able to determine that my GPU was the culprit (for the curious, I go into detail here: http://www.overclockers.com/forums/...k-Screen-Scraggly-Lines-Can-Boot-in-Safe-Mode ).

In my experience, it's immediately apparent when your GPU is overheating - there are lines running across your screen, discoloration across the board, and a forced shutdown once it passed some certain threshold. However, I experienced none of these symptoms (if I saw these, I would have immediately shut the computer off) - the card just up and died.

What should I look into in order to avoid this in the future (aside from monitoring my temps more closely)?

My Specs:

Intel Sandy Bridge i5-2500K CPU @3.3GHz (4 CPUs), ~3.6GHz

8 gigs of ram

Windows 7 Professional 64-bit OS

MoBo: Uncertain, but sysinfo yields the manufacturer as Gigabyte Technology Co., LTD, model Z68A-D3H-B3 (a quick Google makes me think it's the GIGABYTE 6Gb/s USB 3.0 ATX Intel Motherboard)

Power Supply: Corsair 600W (Model: CMPSU-600CX V2), but I've had this for a few years (about... 3.5-4), so the actual wattage is likely lower.

kintaldirk, mysterious circumstances could be that it just died, it happens. It may not have been due to overheating, it may just simply be the something failed in the Gpu and it doesn't work now. I've had Gpu's die with warning, such as artifacts and lines running through the screen, even though it was no where near high temps and I've had one die with no warning at all. It just stoppped working one day never to run again. I've had the same happen on a motherboard as well, the Pc was used as a web browser nothing else and one day it just stopped working. It's unfortunate but happens.

Alright - at least it served me well over its life. I appreciate your input, thanks a bunch!