dhsc19: it could just be related to TeamViewer. it would be easy enough to find out since you say you can always reproduce it - simply reboot, do not run sgminer at all, use TeamViewer and do whatever causes the problem, and then start sgminer. if you still get a lower hashrate then sgminer can't do anything about it.
Old sgminers and cgminer 3.7.2 did indeed have leaks on the GPU, but I fixed them a few months ago when I did the "hot-switching" between Scrypt and Scrypt-N. So any semi-recent build of sgminer should not have leaks on the GPU, it is probably something else.
Tried to drop in marucoin-mod to the last Windows binaries, nothing but HW failures.
Can we get the X13 wrapped up in a new set of binaries please?