Ok, I'm sure this is a wasted post but I have always experienced a significant bandwidth change when I do both Uploading and Downloading at the same time. Ok I suspected that its the rules of networking so i've never questioned it. But I just want to know in the simplest possible definition why does my speeds cancel each other out so badly. I'll demonstrate in a crude description. I Download off the internet at an average of 750kb/s and I can Upload at an average of 85kb/s. If I go both ways I reduce both of those numbers to approximately 65kb/s and 350 to 400kb/s depends on the source. Why would this occur? Now I get these numbers from a bandwidth monitor program (Bandwidth Monitor Pro). Now I figured this would be an ISP thing so I thought that on my LAN these rules wouldnt apply but I started monitoring 4gb file transfers from PC to PC. I notice that there is approx 8mb/s download and 125kb/s upload going on through the bandwidth monitor. Why do I upload when I'm downloading? Is there a way to optimize all this so I get better internet and LAN speeds? I have tried numerous tweaks and tips. I have stuck with those that seem to have a minor improvement. I'll give my equipment specs just in case. recieving PC is 3.2ghz P4 with 2gb RAM sending Pc is 1000mhz PIII with 512mb RAM also tried my laptop 1.6ghz AMD (I think) 512mb RAM Router is a Linksys WRT54G v2.2 firmware v4.20.7 The results are wired only wifi speeds just suck for me 2mb/s LAN 150kb/s internet at best in any circumstance.