Easiest and most convenient way to do it is to download Half Open Limit Fix from http://half-open.com/ and apply the number you want. Works all the time, even with latest TCP.SYS file.
The other issue I notice is that with larger hibernation file, the MFT gets fragmented frequently. I was also reading about this somewhere, can't recall the link.
Many thanks for patching the latest tcp.sys, I was too lazy to run a hex and do it on my own. I do have a question regarding the connection limits. Do I also have to create a reg hack under tcpip parameters and create a new MaxTcpConnections D Word value?