it is fast at the start but then gets slow after 30 minutes of market open. I have to restart it for it to be fast. How many charts do you have open up?
Or maxing out IB's servers capabilities? I called IB many times and wrote many e-mails. After my long time harrasing my whole problems are gone. I think they upgraded me to better server or something like that. I have same setup and same internet... IDK how TWS works perfectly for me now... I am pretty sure, the problem is IB , not users.