Differences btw. Hyper-Threading and Dual-core

Many people are now confused with the technological benefits between Hyper-threading and Dual-core. Now let us clear the doubts about this.

What really confused the people is this picture as shown below:

Picture courtesy of my desktop - Intel Pentium 4 Prescott with HT (3.2GHz)

As usual, the Windows Task Manager will show two boxes under CPU Usage History if your desktop runs either on HT processors or dual-core processors. This is where people will become confused whether their processor is dual-core or HT-based. For more to clear the doubt, right-click the icon "My Computer". Then go Properties. If your processor is Pentium 4 2.8GHz and above, then it's HT-based. If not, like it shows Pentium D or Pentium Extreme Edition, it will be dual-core.

Note: Pentium Extreme Edition is a dual-core and HT-based processor. 4 boxes will show up under CPU Usage History on Task Manager.

Refer to the picture below:

Even though the diagram states dual-processor, let us assume the picture on the left as a dual-core processor.

Dual-core processor has two logical cores with their own L2 cache (this is exception for Yonah architecture (Intel Centrino Duo) which has shared L2 cache). While for HT processor, there is only one logical core but the core is imaginized as two logical cores with shared L2 cache.

The two cores in dual-core processor talks to each other via external Front Side Bus (FSB) while two imaginized cores in HT processor talks to each other directly or sometimes via external FSB.

Dual-core processor outlasts HT processor. Previously, Intel did not intend to have any special technology to help HT processor share the L2 cache efficiently. That's why Prescott processors do not do well in some parts of the benchmarks, especially the games which requires high graphics calculations. Remember NetBurst? This is the worst technology from Intel, according to some reviews in some famous online IT website. It causes Prescott to run hot when full.

Now, Intel has learnt their lesson. In the Yonah architecture, the two cores have to share 2MB L2 cache. Intel has applied Intel Smart Cache technology. This technology will reduce the stress of the processor itself to stree itself to share and allocate the L2 cache efficiently, thus creating heat. With this, Intel Centrino Duo can now run cooler than ever, probably cooler than the coolest from AMD.

Currently, my desktop runs on Intel Pentium 4 HT with 3.2GHz speed. It's Prescott based. It's running hot but managed to keep it as low as 60 degree celcius in half-full. If full, maxi about 85 degree celcius. If idle, about 50 degree celcius. Recommended from Intel is idle - 30 degree celcius, full - 50 degree celcius. OMG! I did not meet it. Anyway, Prescott wasn't that hot. Prescott was hot due to NetBurst - poorest architecture! Now, successor of Prescott, Presler, 65nm based, is running cool. If you water-cooled it, your Presler processor can run efficiently and more faster in graphic-intensive games like TimeShift. Wow!

If you still have doubts with the above stated subject, put it down in the comments section.