I'm using an evga gtx 260 and an msi gtx 260 in sli. The evga was stable w/ a base clock of 714, shader of 1534, and a memory clock of 1230. I got those with evga precision tuner. To overclock the msi one, I went into nvidia performance tuning menu, and set the values. but whenever I run 3d mark or windows index, it throttles the evga card down to base clock 681, mem 1099, and a lower shader 9I don't exactly remember). I've tried setting all the values in that nvidia tuner, w/o the evga precision, and still nothing. Moreover, I tried lower overclocks for each card, and the same still happens. I'm running a core i7 920 @3.8ghz and have a 750 watt psu, if that helps. What should I do?