Hyperthreading

edmond419

Distinguished
Apr 2, 2010
435
0
18,810
Hi All

I want to know the diffference between having Hyperthreading on and off on a Intel Core i3 M350 2.27GHz running windows 7...

I want to know whether if it is ON or OFF. All cases involve Word 2007 with a person typing at 79wpm, using web browser to browse Tom's Hardware-like websites.
-Better performance
-Make the laptop produce more heat or produce less heat (running the same apps in both cases)
-Make the laptop last longer
-Longer or shorter battery life

Thank you all for your information
 
Solution
With HT turned on it consumes more power which means more heat and shorter battery runtime.

I would say ~2% more power consumed at idle and ~10% more power consumed under full load with HT turned on.
To see if hyperthreading is ON or OFF run Task Manager (Ctrl+Shift+Esc) and click the "Performance" tab. If there are two CPU graphs then for a Core i3 it means HT is OFF. Four graphs means HT is ON.

For Word and web browsing you probably won't see any difference in performance, heat or battery life. Those types of programs are normally constrained by how fast the user can type or click links, and that's WAY slower than the CPU.

The only reason you might see a difference with hyperthreading is if the program has to use the CPU heavily. For example a web page with a 3D Flash object showing a continuously moving scene might perform better while doing other work with 4 threads instead of just 2.
 
You can't trust Task Manager all of the time.

Using sminlal's Core i3 example, what happens if you disable one core through the BIOS Setup but you leave HT enabled? Task Manager is going to show two graphs just like it would with both cores enabled and HT disabled.

Just run CPU-Z. It tells you how many cores and how many threads are enabled. A Thread-to-Core ratio of 2:1 would indicate that HT is enabled.