Win98SE for modern gaming and videos? You HAVE to be kidding me. Most of the hardware proposed seems pretty on point, however I'd caution against an SLI or Crossfire configuration in an mATX format/case. Heat and noise would create a BIG issue. I have an overclocked e8400 (to 3.8ghz prime stable) cooled by a Scythe Mini Ninja on an Asus P5E-VM HDMI, 8800gts (512mb), two 500gb hard drives, 4gb OCZ OC'd ram, and a higher end modular Thermaltake PSU. All of this is inside a Lian Li PC-V350 and looks remarkably similar to this setup:
I built this system about 1.5 years ago and it still takes names with pretty much anything I throw at it. It's fairly cool, CPU sometimes creeps up to around 50C and the 8800gts hovers around 56C in intense gaming. The fans ramp up a little during gaming so it gets a little noisy, but nothing you can't easily drown out with your headset or speakers. Fans can be replaced with quieter versions as very easily as well so it will be nearly silent when doing every day browsing etc. I haven't kept up with the BLEEDING edge hardware lately but from what I can see, the ATI and Nvidia have been coming up with some great stuff. The ATi 5850 might be best bang for buck around at the moment (and small enough for mATX). Not sure how I feel about passive cooling for high end video cards in small enclosures...my buddy but one in a Shuttle back in college and he had nothing but issues with the card getting too hot. However those Shuttles had AWFUL cooling on their own...
I built this system about 1.5 years ago and it still takes names with pretty much anything I throw at it. It's fairly cool, CPU sometimes creeps up to around 50C and the 8800gts hovers around 56C in intense gaming. The fans ramp up a little during gaming so it gets a little noisy, but nothing you can't easily drown out with your headset or speakers. Fans can be replaced with quieter versions as very easily as well so it will be nearly silent when doing every day browsing etc. I haven't kept up with the BLEEDING edge hardware lately but from what I can see, the ATI and Nvidia have been coming up with some great stuff. The ATi 5850 might be best bang for buck around at the moment (and small enough for mATX). Not sure how I feel about passive cooling for high end video cards in small enclosures...my buddy but one in a Shuttle back in college and he had nothing but issues with the card getting too hot. However those Shuttles had AWFUL cooling on their own...









