Hyperthreading off = stutters off.

[ZaltysZ]

Originally Posted by klem

Is it better to assign CoD to the first threads of each core in this way or to turn off Hyperthreading in BIOS and assign it to all cores (=15).

And why?

First or second logical core of physical core isn't important. It is important to not assign to both logical cores of the same physical core. You can achieve the same by disabling HT in BIOS (you will have single logical core per physical one), but then you may loose performance in other programs (i.e. HT is really helpful in encoding). I don't use PC just for gaming, so disabling HT isn't very attractive thing for me.

P.S.1: Windows 7 avoids putting threads on same physical core when others are free, unless thread is HT aware.
P.S.2: Some applications check CPU count and then decide how many threads it will spawn. Depending on counting method used, they may simply spawn too many threads for given mask (i.e. you have 4 cores, but give only 2 to application; application still sees that you have 4 cores total and spawns 4 threads, instead of optimal 2). If such applications does not have a way to be told about cpu count or thread count, HT might be problematic and probably should be disabled.

[SEE]

In the Nvidea control panel is the option of 'threaded optimisation' which can be 'auto', 'on' or 'off'. I did some reading using google and there are a wide range of opinions regards this parameter. I just tried the Black death track with it switched 'off'. (some say the 'auto' feature is bugged but may be that applies to earlier Drivers)

I didn't get any stutters or pauses (just a drop in fps as the bombs hit) but should this be 'on' and how does it relate to this discussion regards hyperthreading (especially for us whose BIOS doesn't allow the user to disable HT)?

[klem]

Originally Posted by ZaltysZ

First or second logical core of physical core isn't important. It is important to not assign to both logical cores of the same physical core. You can achieve the same by disabling HT in BIOS (you will have single logical core per physical one), but then you may loose performance in other programs (i.e. HT is really helpful in encoding). I don't use PC just for gaming, so disabling HT isn't very attractive thing for me.

P.S.1: Windows 7 avoids putting threads on same physical core when others are free, unless thread is HT aware.
P.S.2: Some applications check CPU count and then decide how many threads it will spawn. Depending on counting method used, they may simply spawn too many threads for given mask (i.e. you have 4 cores, but give only 2 to application; application still sees that you have 4 cores total and spawns 4 threads, instead of optimal 2). If such applications does not have a way to be told about cpu count or thread count, HT might be problematic and probably should be disabled.

ok I may try that. I don't have bad performance generally but I do get stutters on line.