Hyperthreading question?

[snidy1]

When hyperthreading is enabled, since the OS thinks there's two CPU's, will a 3 gigHz be like two 1.5 gigHz? Or will it actually still be running at 3 gigHz?

 

[ChampionAtTufshop]

its not 2 physical cpus

for normal CPU: when one section of the cpu is working, the other section normally has to wait before the data its waiting for can be processed

for HT, i think its like this: when one section of cpu is working (say FPU) it is able to process like SSE code simultaneously wihtout the waiting period

i think thats how you get two logical cpu's

anyways, its still working at 3ghz, not 1.5 x2

 

[snidy1]

Thank's. Do you think it'll give better gaming performance?

 

[imgod2u]

Games will have to be written to take advantage of it. There are many ways for this to be possible from "helper threads" that pre-loads data to feedback threads that give code hints on how to proceed.

 

[sonoran]

>>>its not 2 physical cpus

Right - it's more like 1.05 CPU's (since the hyperthreading circuitry only increased die size about 5%).

>>>for HT, i think its like this: when one section of cpu is working (say FPU) it is able to process like SSE code simultaneously wihtout the waiting period

Uhhh, not really. Hyperthreading really just prepares more instructions for execution (from two different threads) simultaneously. They still can't be executed simultaneously, but if something stalls one thread, the other is more likely to be there waiting to go. Thus the CPU is actually doing useful work a higher percentage of the time.

When hyperthreading first came out, most of the benchmarks didn't show it doing much. What people are finding out in the real world though, is that it makes for a much more responsive machine any time you're trying to do two things at once. Will it make a single game run faster - probably not by much (until game engines are optimized to utilize it). But it probably will make your game less likely to slow down if your machine decides to start doing something else while you're playing, like running a virus scan, or checking for new email.

Just ask this guy what his opinion of Hyperthreading is recent user comment on THG.

 

[Tom]

Yes, and something to keep in mind that during typical use a Windows XP machine is quite often during more than one thing at a time even if the operator percieves it to only be doing one thing.

 

[orion7144]

I've noticed significant inprovements on doing everyday stuff. When I was uncompressing a file with winrar and checking a file with smartpar at the same time it would take forever. Now with the HT enabled cpu they both move like they were thge only program open.