http://osfree.i2p/forum/viewtopic.php?p=1397
Here's the same results for the 2.6 kernel, which has explicit support for HT: Table 7. Effects of Hyper-Threading on Linux kernel 2.5.32 chat workload Number of chat rooms 2532s-noht 2532s-ht Speed-up 20 137,792 207,788 51% 30 138,832 195,765 41% 40 144,454 231,509 47% 50 137,745 191,834 39% Geometric Mean 139,678 202,034 45% As you can see, being able to update the kernel source and staying on top of improvements can make quite a difference.