gpu artifacts with drivers installed but not without, why?

[Hell Patrol]

http://linustechtips.com/main/topic/447825-artifacting-help/?p=6004451#entry6004451

previous thread above for more specifics

So this is a simple question and the final step in me deducing if i must buy a new gpu. Why would a gpu artifact with drivers installed but without drivers run fine with no artifacts? i'm convinced there must be some hardware reason but i really dont know how it could be, since the gpu works without them (obviously at a low spec)

also sorry about any grammar since im stuck doing this on a phone

something else weird too is this happened all at once, my gpu did not have a single problem until in an instant last night it went bad, after only a year of use and while idle at cool temps at that, read the thread i linked if you want any elaboration