Unless you have a big case fan pointed right at the Ti500, I wouldn't recommend running it with no fan. Hell even with that, I'd say leave the fan on the Ti500. If it's a not-overclocked Ti200 (175 MHz core) it would be more likely to run this way without problem, but the Ti500 (240 MHz) is a very hot beast, hand picked to run at speed (with a fan). The Ti500 definately would start to get glitches and problems with the display after running for any length of time without a fan.