Heres a formal RWIN definition for everyone. Hope this helps and everyone realizes you dont need a fast processor or a gig of RAM to use an RWIN.
The TCP Receive Window size is the amount of receive data (in bytes) that can be buffered at one time on a connection. The sending host can send only that amount of data before waiting for an acknowledgment and window update from the receiving host. Matching the receive window to even increments of the MSS increases the percentage of full-sized TCP segments utilized during bulk data transmission. MSS is the MaxMTU - 40 bytes for TCP and IP headers.
The RWIN default is 8192 bytes rounded up to the nearest MSS increment for the connection. If that isn't at least 4 times the MSS, then it's adjusted to 4 * MSS, with a maximum size of 64K. With the Windows 95 default MaxMTU of 1500, the default RWIN is rounded up to 8760 (1460 * 6). You can greatly improve performance by setting this to a lower value such as 4 times your MSS (MTU-40). The idea is to bring it to a value below 8192. Many people have better success with 6, 8 or even 10* MSS. In some cases, however, manually setting RWIN may decrease performance because it takes the control away from windows, and if the MTU is negotiated to a different value, then the size of the RWIN is no longer an whole integer multiple. For this to be effective you must make sure your MTU is set where it will not be negotiated to a lower value.