slow green harddrives can cause texture pop in games. to many partitions can also slow the drive down, upto 10% per partition... and 2tb drives should never be your primary drive. there just to big and often much slower than there 1tb counterparts.
i guess your running at near max settings as managed pretty high almost maxed while playing mp3. but i have a raid 0 system so i dont often notice texture pop. check the speed of your drive if its under 80MBps then you may have your answer but if its 100-240 i would say what your seeing is normal for the game. no matter how well programmed texture pop will always be there in 1 form or another fast drives can hide it but if your actively looking for it you will see it...
if you can find it download a demo of rage and you will see a real texture pop issue. you can turn around and the textures right in front of you will be blured, then middle filtered the hi rez filtered taking about 3 seconds in total to finish rendering... but if you had a raid setup this would be hard to spot even b4 it was fixed because it was down to the game loading the textures as needed instead of having a library of them in memory...
i dunno if the demo has been patched fully but it is still available on the id soft site... try it and see if you have unlimited internet.
now for the nuts and bolts... when distant objects are rendered because they use polygons they are rendered at lower rez to save memory. although mp3 uses 25gigs of disk-space you can still see the odd small badly rendered object.
if you look for it you will see a semicircular horizon and beyond that the objects are slightly less detailed, when you bring them within that horizon they will sharpen up and this is most likely the texture pop your on about. this is often associated with draw distance of the game engine and the gfx cards memory. the horizon will be a few yards in front of you (stalker cop) your running low on memory, if its a good engine most of the time the horizon will be hidden by foreground and background objects. mp3 on the whole is a good engine... what you can do to see if its a memory issue is turn off msaa and just use the other aa option but at low. the memory usage should drop quite a bit freeing it up to increase the draw distance... go back into the game and see if the problem persists. if it does it just means its a bad render and not a gfx memory limit issue. even though your gpu is a dual gpu it halves the total memory for each meaning the effective memory you have for a screen is actually half the total. you may haver 3gigs but in reality your only allowed to use 1.5 per screen image. so you have no more memory in real terms than if you were using a single gpu with 1.5 gigs. this is the memory issue im on about not a broken mem chip or anything of that nature.
end result is its likely to be a driver issue or a game engine optimization issue rather than a hardware fault... nice system btw. im in the market for a 590 cough, donations welcome