... that is the question! In February i decided to upgrade from a perfectly good Q9550 to an i7 920! To cut a long story short, i had the Q9550 overclocked to 4GHz and got the 920 to the same but something didnt feel right. The new i7 system didnt feel as responsive, the boot time seemed longer, games didnt load or close as quickly and media player / vlc didnt enjoy being moved about the desktop while playing video. So it dawned (a few days ago) on me that one of the major difference between the two cpu's was hyperthreading. I turned it off and it appears to have worked! My question: Does hyperthreading actually help when it comes to gaming and media playback? Do most people turn it off when overclocking the 920 / 930?
Most overclockers will turn it off when exceeding much more than 4.2/4.4ghz. Personally I kept mine enabled and still manage a very stable 4.2/4.4ghz overclock on my 930. I would not have expect you have many issues with HT at 4ghz. Enabling HT can add as much as an additional 10c on your temps and will cause the cpu to require more juice. So you may find that if you increase your voltage on the cpu slightly you could re-enable the use of HT. What temps and voltages are you getting/using atm ?
From memory, hyperthreading is very effective at speeding video encoding - ~20% plus difference. It's also pretty good for other highly threaded applications like compression/decompression. When it comes down to it, there's very few instances that you'll be using 4 threads however, let alone 8, so there's very little benefit to keeping it on. I do keep it on, but that's just because it is working fine on my 3.8GHz clock. As mentioned, may people turn it off to enhance stability at higher overclocks. Games don't need it at all, neither does media playback.
The main benefit I've seen is in video encoding and that only with software that recognises all the cores. My system feels just as responsive whether it's on or off and as mentioned above having it on adds quite a few degrees to the temps. I can't understand why turning it off would make a difference to responsiveness.
