I have three machines connected to a cable modem and firewall / router. ISP is Comcast with nominal bandwidth of 3Mbps on the download. A 5-year old PIII machine with a 100Mbps NIC consistenty shows about 3Mbps in download speed as measured by various bandwidth testing sites (PCPitStop, etc) plus downloading big files from sites like Microsoft. Two much newer WinXP Pro machines with Giga NIC's can only get 2Mbps or less - at least a third slower (and even more so for big files from Microsoft). All machines run IE 6.0 and Zone Alarm Pro (and no Win firewall on the XP machines).
Any ideas on why the Win98 box is faster and if there are tweaks or settings that might boost the XP machines?