A higher HTT don't help, well at least on my S754 3200+ it didn't.

HTT is how fast the processor talks to IO subsystems. (NIC's, other cpus ect) In our case, the HTT exceeds the rest of the hardware in speed so it makes no diffrence.

However with PCI-X it might actually start to make a diffrence.

Read more about hypertransport here:
http://en.wikipedia.org/wiki/HyperTransport