question about intel core i7 and Hyper-threading

[Yo-Yo Freak]

*i searched everywhere and couldn't find a streight answer to my question so forgive me if this has alredy been answer*

Quote from Wikipedia:

"Re-implemented Hyper-threading. Each of the four cores can process two threads simultaneously, so the processor appears to the OS as eight CPUs."

ok so on to my question, i know that the i7 is 4 phisical cores but with Hyper-threading it is 8 logical cores. my question is this: does this mean that if you run 1 instance of WoW off of each logical core would it put the same amount of stress on the physical cores as running 2 instances of WoW at the same time on 1 of the physical cores? so in theory you could 10 box on 1 i7 processor (1 WoW per 6 logical cores and 2 on each of the other 2) and have the same result as 10 boxing with 2 quad core processors (well maybe not the same but roughly the same). i have been reading alot all over the web and there arent any reviews that state anything for situations such as this, like comparing the use of 2 logical cores to 1 physical core. Thanks in advance everybody ^_^

[Freddie]

Hyperthreading doesn't allow a physical core to do twice as much work in the same amount of time. At best, according to Intel's claims, it increases the capacity by about 30%. But the actual improvement depends on which applications you're running. In actual testing, it turns out t
hat some programs -- including some games -- apparently run slower with hyperthreading turned on. For example, take a look at these benchmark results:

i7 Hyperthreading Test on VR-Zone

They report that Far Cry 2 runs 5% slower -- not faster -- with hyperthreading turned on.

Edit: Those tests show single instances of applications but your question is about multiple instances, and maybe multiple app's always get an improvement. But until somebody runs some tests with multiple WoW's I don't think we can know.

[matexoza]

im using the i7 and i dont know about 10 but id say atlest 6-7 np it would do that with low lag and my systems runing with 4g ram i ran 5 anarchy onlines with no lag and that game taks a little under double what wow dose to run

[not5150]

WoW isn't multithreaded, so there's little benefit to be gained from hyperthreading.

However, other architecture improvements like the chip's microcode and motherboard maximum RAM would help multiboxers. Most of the Core i7 mobos have 6 memory slots (2 sets of triple-banked DDR3) so you could put a maximum of 24 GB of RAM on the mobo.

I suspect you might be able to get 10 WoWs working if you had sufficient RAM.

[Yo-Yo Freak]

thats kind of what i thought but i wasn't completly positive. thats funny it acualy slows down games weird. thanks for clarifying that for me i couldn't find anywhere that acualy stated that. i guess if you think about it its kind of like commen sens but i just had to be positive lol.

[Freddie]

[quote='not5150',index.php?page=Thread&postID=15857 1#post158571]WoW isn't multithreaded, so there's little benefit to be gained from hyperthreading.[/quote]
I don't think we can draw that conclusion because (a) WoW in fact has multiple threads (26 according to Task Manager), and although the degree of concurrency may be small it's not zero. And (b) we're talking about running multiple applications at the same time. WoW isn't single-threaded but to be very conservative, let's say that it is. If we run (say) eight instances of a single-threaded app on a four-physical-core CPU, the result is similar to running four instances of an app that has two perfectly independent threads.

I found some more benchmarks showing hyperthreading on vs. off. Unfortunately these benchmarks are all single instances of apps instead of multitasking, but I think they show the importance of testing exactly what we're curious about.

[url='http://www.tomshardware.com/reviews/Intel-Core-i7-Nehalem,2057-12.html']i7 and Hyperthreading on Tom's Hardware[/url]

[Tsunami]

For Hyperthreading to work properly the program needs to be written to take advantage of hypertreading. when intel tried it the first time the processors were only single core and there where several physical and software issues that limited hypertreading then. with out getting into the programing aspects of this, you cannot treat a virtual core the same as a physical core.

but hypertreading is not the biggest improvement to the core i7. what make the i7 so fast is how it deals with memory on the chip itself. beside using tri-channel memory (which basically means the cpu can address 50% more memory at a time (3 is 50% more than 2)) the i7 controlls the memory on the chip itself. which is much faster.

but to answer the OP. until blizzard makes a patch to optimize wow for hyperthreading you wont see a performance boost. where you will see it is when running window and your gpu. which can be easily update to take advantage of this technology. but right now the technology is far more advanced than the software, it will take a couple of years for the software to catch up, and if intel doesn't support this than neither with the programers.

[Freddie]

[quote='Tsunami',index.php?page=Thread&postID=15860 5#post158605]For Hyperthreading to work properly the program needs to be written to take advantage of hypertreading. [/quote]
Microsoft says, "In general, multithreaded Windows applications perform better when running [b][i]unmodified [/i][/b]on an HT processor than they do on a similarly equipped single-threaded processor." (My emphasis.)

They go on to suggest a way that applications can take special advantage of hyperthreading -- by setting thread affinities in a certain way -- but this is icing on the cake.

This is from section "6.2 Improving Application Performance on Hyper-Threading-Enabled Systems" in

[url='http://download.microsoft.com/download/5/7/7/577a5684-8a83-43ae-9272-ff260a9c20e2/Hyper-thread_Windows.doc']Microsoft White Paper on Hyperthreading[/url]

[wowphreak]

(3 is 50% more than 2))

did someone not get there caffeine in the morning or what?