Hyperthreading...any good? (Shed's Confusion)

[Shedlife]

This is me totally guessing as I'm not having much look reading around BUT, does HT effectivly split my 3GHz between the two threads i.e 1.5GHz per thread? I've just turned HT off (it was its factory default) and COD4 quits slower (back to the main menu) but gameplay wise i THINK (could me being too hopefull) is running even faster (30-75FPS). Could anybody guide me, to wether HT should be on or off, and are there any benchmarks (for games) that show the performace difference.

Cheers,
Shed =]

[Lynx]

HT means that you get two threads to the CPU, meaning basically two connections, giving more bandwidth and better performance, turn it back on. It isnt really going to affect performance that drastically honestly, they got rid of it in Core 2 duo cpus because it was useless.

[wonderlust]

But it has returned in the I7 Series :D

[Lynx]

Where they are hoping it will work. Technically returned with Atom, but i will let that go.

[wonderlust]

Lol I cant argue, tests I have seen (server type apps) show it works, for the desktop I am not so sure

[Shedlife]

Well, Half life 2 episode 2 runs pretty slow 25fps...and the graphics aren't as good as cod4 (it even runs slower than crysis :P) on windows task manager it shows that it only uses 1 thread as the other APPARENT cpu is totally idle (does this mean its only using half the processors power?)

[Lynx]

No, means it doesnt hyper thread, hyper threading doesnt give twice performance, a fraction of that, you dont have a dual core.

[Shedlife]

Well yes i know that LOL but i meant is the processor spilt into 2 so 1 thread feeds 1.5GHz and the other thread feeds the other 1.5GHz? Or do they both feed the same 3GHz?

[Lynx]

No, both threads get 3ghz.

[Shedlife]

Right good, sorry to keep draggin this on but i just remembered that on COD4 (on windows task manager) with is with HT turned on the CPU is used at around 60-70% and without HT its used a straight 100%. Is the cpu being used 100% w/o HT because its got a smaller bandwidth or is it because COD4 can utilise more of the processor?

[Aaron]

Best thing to do is use fraps. Run a benchmark of a few games with the exact same settings, but one with HT turned on and one with it turned off.. Then you'll know :)

[Shedlife]

Best idea I've heard in a longg time :D ;) I'll return with my findings...just in case anybody cares XD

[Shedlife]

My findings (for anybody know cares to look) are that HTT, won't improve your games FPS, but it does allow your PC to multitask alot more effectively. So all in all keep HTT ON! :D

[Aaron]

Best idea I've heard in a longg time :D ;) I'll return with my findings...just in case anybody cares XD
Thank you. I accept rep in abundance. ;) :lol:

[Lynx]

So you pretty much tested my fact and found i was right? it does hardly anything.

[Shedlife]

Yeh, gameplay wise HTT is more or less useless except loading times are noticble quicker, but for programers and stuff like that its worth having than no having.

[Audigex]

Turn if off if you heavily use single-threaded applications, otherwise it's better to leave it on. It should help even more with more recent (designed for dual core) programs.

It's main use is increasing throughput to the CPU - by the time it was implemented clock speeds had hit a relative high and the big problem was getting the data in fast enough to be processed.

With core2 chips being back in the lower clock bands again (1.2-2ghz then 2-2.8 for the most part) it wasn't so much of an issue and became useless again, especially when there were naturally two "ways in" through the two cores.

With i7 the clock speeds are on the up again (past the 3ghz barrier being especially important) and while bus speeds are on the up too, the thought is that it should be applicable again.

[Shedlife]

I here by name Audigex the MASTER :D thanks ever so much, you nailed that bad boy :P