I am wondering if optimizing your TCP settings would be helpful to certain trading software, for example, for someone that sends a lot of orders through API with TWS, etc. It looks like there are quite a few settings that could effect your network performance (MTU, Selective ACKs, Max duplicate ACKs, MaxConnectionsPerServer....just to name a few) . I came across several free TCP optimizers. I downloaded one of them called SG TCP Optimizer. It shows your current TCP settings and also recommends optimal TCP setting for your PC. I haven't changed any of those settings yet because I don't want to screw it up. I would like to hear from others who have optimized (or messed with) those TCP setting, and if the results were positive.