My P4 Willamette @1.7 Ghz is now 3.5 years old. Gigabyte GA-81RX Mobo. 768 MB PC 2100 RAM. 2@ 120GB IBM/Hitachi HDD w/8MB Cache. Windows XP Home SP 2. Mostly use this system for web surfing and music playback via E-Mu 0404 PCI sound card/ASIO through J. River Media Center--analog output to Hi-Fi receiver. My only real complaint is that when web surfing just about any use of CPU causes stutters in playback. I'm also concerned that this system is becoming obsolete--soon impossible to upgrade at all. I would like to be able to use the RAM and the HDDs on the upgraded system at least initially to spread out the expense. Eventually I'll go to faster RAM and bigger HDDs. The existing Mobo will accept a P4 Northwood up 2.6Ghz but still with 400 FSB. I don't think that makes any sense. So that means a new CPU/chipset/Mobo for openers. I've got two Mobos in mind: Gigabye GA82PE1000Pro-G Socket 478 Intel 865 PE chipset; or ASUS P4P800-E Deluxe Socket 478 Intel 865PE. For CPU I'm considering the P4 3.0C Northwood 800MHz FSB 512KB L2 Cache Socket 478. I don't see any problem using the existing ATA 100 HDDs. The specs on the two Mobos call for DDR 400 (PC3200) RAM. Can I temporarily use the existing PC2100 RAM or do I need to buy new RAM from the jump? What about power supply? Current is 300 W in original Inwin case. Any recommendations on alternatives would be appreciated. Thanks.