Thank you for the response. I can't find a version number anywhere in the GUIMiner files, but entering D under the intensity does work and it also brought my hashrate to the 20s (down from 600+). I've noticed intensity has no effect on gpu usage, doesn't matter what I set my intensity too, my gpu usage stays at 97-99%. I've also found that I have to bring the intensity to 12 or under to stop the slowdown of my pc and it's still very noticeable in videos. I think my problem stems largely from this. I'm wondering why the Bitcoin clients actually leverages usage and the LTC ones don't.

Going to try out CGMiner/CGWatcher combo tomorrow. Although I spend a lot of time at the computer, and since I have to drop the intensity so low to avoid the lag I'll have to look into how much that drops the profitability of LTC compared to BTC. If I can't find a solution, I think I'll end up changing to CGMiner/Watcher for BTC anyway.