Signal Tap too slow on RHEL 5.5 64-bit

I am running Quartus 11.1 SP1 on a RHEL 5.5 (64-bit machine ) and have followed the steps in the USB baslter guide.

Still signal tap is much much slower than windows. for 1100 signals, it

tales 3-7 minutes and fails more than half the time.

On windows, the same thing works great!

Any ideas what could be wrong and how to fix it ?