CPU Core's and Hyperthread's performance?

[XDXD_4U3IF1P]

Hi All,

 

Ok so my question is if an application doesn't use more than 4 cores (i.e a FPS game), is it better to turn Hyper-threading off for more CPU performance (assume the game is very CPU intensive)?

 

i.e does hyper-threading itself demand resources? Is hyper-threading even being used in this case? i assume a hyper-thread is not as powerful as a true core anyhow?

 

Next question, if an application (i.e another FPS game) could use more than 4 cores, let's say 6 but you have not maxed out the first 4 cores should you load them (by turning hyper-threading off) or let the draw spread over the 4 cores, and in this case 2 hyper-thread's for best performance?

 

I realise I may not have worded this well, it's a very new area for me to look at and I appreciate learning off you good people.

 

 

[GrobfootGaming]

Nope! hyper-threading isn't as powerful as a true quad core, but it definitely makes the processor a little quicker.

[Nena Trinity]

10 minutes ago, GrobfootGaming said:

Nope! hyper-threading isn't as powerful as a true quad core, but it definitely makes the processor a little quicker.

At multi-threaded apps or games yes, if the game is optimized for dual-cores or worse then no...

[Citadelen]

Hyper-threading is effectively running two threads off of one CPU core, it does not require any resource, and only in situations of poor coding will having it enable in games that can only operate two/four threads hurt performance.

[GrobfootGaming]

17 minutes ago, Nena360 said:

At multi-threaded apps or games yes, if the game is optimized for dual-cores or worse then no...

 

true, but now-days games are not optimized for dual cores.  

[agent_x007]

Hyper Threading is using what Single Core has to offer (ie. it doesn't uses it).

Basicly :
CPU must decode something, before doing it (data, instuctions, etc. have to be "downloaded" from SSD/RAM or cache, first).
When one thread waits for memory/cache to deliver, CPU execution part idle cycles "pile up" (ie. ALU's and FPU's are doing nothing).
But, IF U have more threads per one core, second thread may use the "free" ALU's and/or FPU's when other one is waiting for data. This is the case when HT gets things done faster (compared to context switching ).
Best results from HT come, when on one CPU, first thread is heavy decoding and light execution, and the other is light decoding and execution heavy.

"100% CPU load", cannot tell U what part of CPU Core's "front-end" and/or "back-end", is at 100%. CPU Load means nothing for HT. 
The most important thing for Hyper Threading, is what parts of CPU are most/least used for both threads decode/execution (priority for threads is also important, otherwise U can get visible performance degredation [when two seperate threads are executing on the same core]).

[XDXD_4U3IF1P]

Ok,

 

I thought this one could be deep.........

 

So assume an i7 is being used, and the application being run is poorly coded in this aspect, and doesn't use more than 4 cores.

 

Turn hyper-threading off for better performance, as the game is CPU intensive?

 

The application is of course Arma 3 that im referring to.

 

If hyper-threading is straight forward to turn off, I can test later but I don't want to screw my system up, if that's possible I likely will...........

[incarnate]

16 minutes ago, ShoshinUK said:

Ok,

 

I thought this one could be deep.........

 

So assume an i7 is being used, and the application being run is poorly coded and doesn't use more than 4 cores.

 

Turn hyper-threading off for better performance, as the game is CPU intensive?

 

The application is of course Arma 3 that im referring to.

 

If hyper-threading is straight forward to turn off, I can test later but I don't want to screw my system up, if that's possible I likely will...........

You won't screw it up and to my knowledge the only game that had worse performance with hyperthreading turned on was far cry 3. Hyperthreading itself doesn't use any additional resources, it uses parts of the core that aren't in use at the time to run another line of code. If the main core (not the virtual hyperthreaded one) is busy then the hyperthread has to wait.

 

Try turning off hyperthreading, but I doubt you'll see a difference.

[Nena Trinity]

53 minutes ago, GrobfootGaming said:

 

true, but now-days games are not optimized for dual cores.  

Thank science for that!

[Prysin]

you shouldnt see any difference between it on or not. However if you got slower memory, or high latency memory, then memory bottlenecks is more prevalent.

 

Hyperthreading is MOSTLY used to hide memory/fetch/bandwidth issues

[XDXD_4U3IF1P]

Having looked at a few more youtube resources, it would seem the general opinion is that -

 

Turning hyper-threading off (in games like Arma 3 and GTA5) may give a slight bonus to the following -

 

1. min fps

2. CPU temp

 

But, and heres the disappointment only a couple of FPS.

 

I'll try it, as the min FPS does help me out more than most as i'm running on a gaming laptop.

[XDXD_4U3IF1P]

1 minute ago, Prysin said:

you shouldnt see any difference between it on or not. However if you got slower memory, or high latency memory, then memory bottlenecks is more prevalent.

 

Hyperthreading is MOSTLY used to hide memory/fetch/bandwidth issues

ah interesting, my laptop has 32GB of DDR3, 800MHz (slow?), Latency (CL) 11 RAM according to CPU-Z.

 

Am I reading something wrong as im sure the RAM should be 1600 i.e not 800?

[Prysin]

it is 1600MHz

DDR stands for Double Data Rate. So if CPUZ reads 800, you multiply that by 2 to get ACTUAL speed

[XDXD_4U3IF1P]

yeah thanks, minor panic there............

[incarnate]

46 minutes ago, ShoshinUK said:

Snip

Cpus that display a gain in performance from higher speed memory are cpus with low cache. Once a cpu runs out of cache it has to start using system memory to cache instructions, which is far slower than cache. It has nothing to do with hyperthreading so you don't need to worry about that.