Question about hyperthreading

[MrSmithers]

I have a question. I know that basically hyperthreading creates two logical processors as seen by the system. My question is, what if someone is running a giant application that needs all the processor. For example, when I play Battlefield Vietnam the game uses only 50% of my CPU speed, and the task manager shows that it is using all of one of the two processors. In this case, would it be better to not run hyperthreading? Just curious on how this works I guess. Thanks.

Smithers

 

[Duvie]

Basically all applications that are not HT enabled or dual processor capable will max at 50% which means 100% load on one cpu. If you turned off HT the task would be 100% but it is likely the performance will be identical to neglible. Thugsrook has a thread that shows virtually no change from HT or no HT....

NOw the key wil be if you game but say wantto do an encoding or maybe running dvdshrink, virus scan, distributed computing you can get more done at once...

Example....

If I run UT2k3 with HT on and off I get virtually identical score in the demo aswell as fraps gives me same average fps over a prolong period of time. Now if I ran SETI at the same time I was able to game with about a 5-7% loss in fps (still very playable) yet I was able during that time to actually give cpu cyces to the SETI work unit. With my barton the game play satyed still full speed with the 2 apps but absolutely no cpu cycles were given to the SETI unit. Meaning that nothing was done and the unit was virtually no fiurther along then if I started it when I was complete.


To expand on the above cpu utilization....

TMPGenc 2.52 = with Multiprocessor enabled = 100% load (up to 22% increase in speed in encoding)
Autocadd 2004 Architectural Desktop = with multiprocessor enabled in rendering = 100% load (19-22% in all rendering and animation rendering

With Folding Home or SETI they are not HT enabled but starting 2 unique instanes can result in up to 40% increase. 2hrs 7min to get 1 unit done.....2hrs 59min to get 2 units done


More and more programs are becoming HT enabled but most can take positive advantae when ran in multitasking mode.