Question about hyperthreading

[Aaralli]

I'm wondering if two cpus made by the same company around the same time with the same or a very similar clock speed and the same number is cores would have different TDPs if one had hyperthreading and the other didn't. Anyone know this?

[Electronics Wizardy]

Hyperthreading does use more power. You can test this very easily on your pc. This also varies with load.

 

This might not affect tdp, as its not the same as power usage.

[Ocrovelo]

Yes, hyperthreading/SMT uses more power.

[Aaralli]

4 minutes ago, Electronics Wizardy said:

Hyperthreading does use more power. You can test this very easily on your pc. This also varies with load.

 

This might not affect tdp, as its not the same as power usage.

So, there's a good chance that heat output will be greater? Would it be double, since it's twice the number of logical cores?

[emosun]

1 minute ago, Aaralli said:

Would it be double

no

[MrChemistryCow9]

6 minutes ago, Aaralli said:

So, there's a good chance that heat output will be greater? Would it be double, since it's twice the number of logical cores?

As Linus said in the what is hyperthreading techquickie video, it's not that much so maybe 10-25 watts.

[Drak3]

6 minutes ago, Aaralli said:

So, there's a good chance that heat output will be greater? Would it be double, since it's twice the number of logical cores?

No, because the chips are physically the same. Heat output might increase somewhat, depending on the workload, from the more efficient use of resources, but it won't be doubled.

[Curious Pineapple]

6 minutes ago, Aaralli said:

So, there's a good chance that heat output will be greater? Would it be double, since it's twice the number of logical cores?

Some parts of the core are duplicated, but not all. I think on Intel systems the second "core" has it's own integer and floating point exceution unit but shares cache and access to the interconnecting bus. The FX has a shared floating point unit, but as bugger all is designed around the fact, it hurts performance when 2 threads on the same core try to run floating point instructions at the same time. Not a clue about ZEN as it's been quite a few years since I've actually given a toss about keeping up with hardware. I still use a Core2Quad machine and have just put an LGA771 Xeon machine into service.