Should I disable hyperthreading in an Intel CPU

cpuhyper-threadingintel-core-i5

I have a laptop with Intel i5 M430 2.27GHz.
The CPU has TWO REAL cores but it also has some kind of virtualization so Windows sees it as 4-core.

In a REAL dual core CPU, a single threaded program will run in a single core at 2.27GHz. Right?

My question is, in my 4-core CPU, the same program runs at a speed of 1.13 GHz? (2.27 / 2)
I mean, the frequency of each real core is split in two in order to simulate a 4-core CPU?

I need to know for to run a CPU-hungry program at maximum speed. If I run two instances of that program I will finish my data processing two times faster, because I have two real cores. But if I start 4 instances I will finish the processing 4 times faster or is this '2 extra virtual cores' thingy another eye-candy feature from Intel?


Update:

I used CPU Overload to start 2 and 3 very CPU intensive threads. In Resource Monitor the "CPU-Total" graph shows only 50 and respectively 75% utilization.

Best Answer

You have a CPU with hyperthreading technology. You can't change this, but don't worry, you won't have any performance loss; actually it increases your system's performance.

Note that the CPU clock is not equal to CPU performance. The clock is not divided by two for two threads.

Update/conclusion: As already mentioned in the comments, in some (most?) BIOSs it is possible to turn off the hyperthreading. But that will not bring any performance enhancements, due Intels thread management is intelligent enough to use only as much as needed.