Your computer's video may affect the speed of Prime95! This applies to systems with video on the motherboard, sharing your main memory. George Woltman says it is because of the memory bandwidth used for video.
Two weeks ago I got a 1300MHz Athlon, with 384MB of PC133 RAM. The video is on the MB, it shares memory. I noticed that the benchmarks were about half as good they should be! I discussed it with George, and he came up with the idea of testing the video. Here are per iteration times for 13,500,000, based on video mode: resolution color depth MB video memory time (sec) 1280x1024 16 bits 2.5 0.237 1024x768 32 bits 3.0 0.204 800x600 32 bits 1.8 0.171 1152x864 16 bits 1.9 0.168 1024x768 16 bits 1.5 0.156 800x600 16 bits 0.9 0.140 Generally, the more video memory used, the slower Prime95 runs. I have the power saver cut off the video after 10 minutes, and then the iteration time goes down to 0.121 seconds - almost twice as good as the worst time, and along the times for other Athlons of similar speed. So if you are buying a computer, it is better to get one with a real video card. If you're running Prime95 on a computer that has video built in to the motherboard, try this experiment, and have the video turn off after a few minutes of inactivity. Also, you can consider using a lower resolution or color depth if you want higher performance from Prime95 while you're using the computer. +---------------------------------------------------------+ | Jud McCranie | | | | Programming Achieved with Structure, Clarity, And Logic | +---------------------------------------------------------+ _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
