This is not low FPS. Even in your system FPS is never an issue, as 40FPS is above what the human eye can readily detect anyway. That is why 25FPS is minimum, however anything much over 30 - 40 is a waste of time. In fact many monitors will lock the 60FPS regardless making synthetic benchmark scores meaningless.
The issue here is video tearing which, if not fixed by v-sync, then is very much likely to be an underpower 12V rail feeding unstable voltages to the GPU, which can cause all types of graphical annomalies. This is also plausible due to the high powered GPU installed.
The FPS comment was irrelevant as in no way is this linked, particularly if he is getting 60 - 70 FPS.
It is very unlikely that with v-sync enabled that tearing would continue, so I would suggest we find out what PSU the OP has.
Essentially a well set up system shouldn't show any tearing so if the vsync solution fails, time to look at power.
TO THE OP
What PSU do you have?
What version of Windows are you running? (32bit / 64 bit)