2nd opinion?

I have an EVGA 7950GT that runs stock @ 600/725MHz and is air-cooled at 45c/idle & 55c/load. I overclocked it effectively to run @ 700/900MHz, 50c/idle & 75c/load. I am experiencing no artifacts whatsoever for the past few weeks. The difference is very noticeable, doubling framerate in some higher-end games I've tried, and scoring a higher benchmark in general. I would just like a second opinion as to whether this is a good idea, and I also had a few quick questions:

- Is this killing the card or optimizing it?
- Would drawing voltage (for a 2nd heat-sink fan) by wire-tapping from the card's main fan cause problems?
- Are these idle temps normal for 0-1% usage?

Some notes:
- This is an older machine (Dimension 9200). I am aware a new card is a solution, but this is a $0 budget upgraded-to-hell-and-back machine.
- The temperatures might run *hotter* than normal, but it is a constant 75-80 degrees where I live at the coolest, so please keep that in mind.

1. Optimizing.
2. The card's fan controller is unlikely to appreciate that.
3. Yes.

75c isn't bad for a full load temp really, 7950s are toasty little buggers. If you haven't cleaned the dust out of the heatsink recently that may help temperatures a bit.