Tuning XP TCP parameters is a a black art and thankfully Vista and Windows 7 have fixed this.
DavidR, it looks like TCP Optimizer helped your connection speed ???
Yes, not so much the connection speed, but it looks like my old dial-up optimizations TCP Receive window settings, etc. were throttling my fast broadband connection.
i got that idea saying new release is design for 64-bit, because 5.0 is stable only in 32-bit and in 64-bit is incomplete. so .1 means they add only 1 feature in the program 5, and the last 3 number is the number of compatibility that has been solve 
only my point of view
i am not familiar with TCP but i will try
Thanks!!!
If it were a 64bit application, guess what, it wouldn’t run on a 32bit OS.