Difference Between Cores & Threads

[Sreno1]

I have heard that threads are simply "virtual cores" and they are better to have than to not have. I want to know what exactly they do as some CPUs have different amounts of them.

[bgibbz]

2 minutes ago, Sreno1 said:

I have heard that threads are simply "virtual cores" and they are better to have than to not have. I want to know what exactly they do as some CPUs have different amounts of them.

 

[Imakuni]

^This.

 

Change the name to "SMT" instead of HT for AMD's upcoming Zen.

[Electronics Wizardy]

Its SMT

 

It lets you have mulitple paths of code running on one cpu to reduce bottlenecks. The benifit depends on the cpu and the use

 

For single threaded programs it won't help and may make it worse due to scheduler problems

 

On intel x86 there is normally a 10-30% improvement with multithreaded programs.

 

On architures like POWER8, you have 8 threades per core and a 2x speed improvement with SMT on.

[xephoneration]

For in depth info, for simple terms, core count is the physical number of cores on the CPU die itself. Thread count is the number of individual application threads which can be executing simultaneously on the CPU itself. Without any additional or special hardware.

[Ronald Browen]

so what is better one core with hyper threading or one core with 2 logic cores. performance wise.

[Imakuni]

13 minutes ago, Ronald Browen said:

so what is better one core with hyper threading or one core with 2 logic cores. performance wise.

They are the exact same thing. Remember, HT is just a fancy name for 2 logical cores per physcial one.

 

Your question could be re-written to: which is more, 6 bananas or half a dozen?