Vista & Hyperthreading


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Since HT seems like a concept that has fizzled out with Intel, Does vista benefit from HT or would it have more benefit out of disabling it. I ask because it seems like a gimmick and how the only real benefit is if the software is threaded to take advantage of the "Technology". Since Intel no longer has this with their newer processors, does Vista perform better with HT vs. without?

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i agree with icefusion - tried it disable and enabled. The CPU sidebar monitor app also detects it as two cpu's and you can see the bar's operating at different %'s

so yes, leave it on :)

  • 9 months later...

I know this is a bit of a bump, but hey there is some useful info I collected below.... basically it shows that hyperthreading doesnt have any major impact on 3dmarks

  Quote
Some 3DMark03 benchmarks using larry's drivers on Vista 5150 - the 97.34 vista drivers are really slow when compared with 67.66.... wonder if the later vista drivers run any better.... is there anyway to get aero to run on XP drivers?

also hyperthreading doesnt seem to play any major role in the benchmarks

67.66 Windows Classic

1280, 1280 (Hyperthreading)

1260, 1280 (Single)

67.66 Windows Basic

1279, 1280 (Hyperthreading)

1281, 1278 (Single)

67.66 Windows Aero

(N/A)

---------------------------------

97.34 Windows Classic

737,729 (Hyperthreading)

722, 721 (Single)

97.34 Windows Basic

737,732 (Hyperthreading)

716,722 (Single)

97.34 Windows Aero

728,731 (Hyperthreading)

723,719 (Single)

Actually, HyperThreading performance is a "hit or miss" kind of thing. It makes the system think it has two logical cores when it really has one, and because of this the OS queues two threads to be processed; however, the second thread isn't processed except in the event that the first thread is stalled. Once the first thread is ready to go, though, it interrupts the second thread which becomes dormant until the first thread stalls again.

As you can see, HTT can cause application performance to deteriorate or marginally improve, so I would say unless you have a single core CPU you should disable it.

  HeartsOfWar said:
Actually, HyperThreading performance is a "hit or miss" kind of thing. It makes the system think it has two logical cores when it really has one, and because of this the OS queues two threads to be processed; however, the second thread isn't processed except in the event that the first thread is stalled. Once the first thread is ready to go, though, it interrupts the second thread which becomes dormant until the first thread stalls again.

As you can see, HTT can cause application performance to deteriorate or marginally improve, so I would say unless you have a single core CPU you should disable it.

Exactly what I was going to say, well probably better worded. Sometimes it helps by a small percent but in the situations it hurts the % loss are greater then the %'s when it helps.

Intel easily could of had Hyper Threading on Core 2 but the performance boost just isn't worth it.

  _kane81 said:
I know this is a bit of a bump, but hey there is some useful info I collected below.... basically it shows that hyperthreading doesnt have any major impact on 3dmarks

This is a pretty useless benchmark for multithreading. Try running something like Cinebench, Lightwave or the LAME encoder. You'll see a marked increase in performance well outside of the margin of error.

  _kane81 said:
I know this is a bit of a bump, but hey there is some useful info I collected below.... basically it shows that hyperthreading doesnt have any major impact on 3dmarks

that's on a beta version of vista, btw.

we're almost at vista sp1 now.

  Quote
Since Intel no longer has this with their newer processors

Hyperthreading made sense with the Pentium 4 pipeline, it was very long, and it made sense to be able to do more than one thing at a time.

With the newer processors, they're more efficient, and at the same time, trying to implement Hyperthreading would be pointless.

If your CPU has HyperThreading, just leave it enabled. The benefits outway any negatives (and I'm not even sure there really are any). Obviously, a multi-core CPU is far more desirable, and I'm pretty sure Intel doesn't even bother with HT in newer chips, though I could be wrong. The idea behind HT is still useful, though - IBM makes good use of a similar technique (SMT) all the time.

Oh.

Just found this:

http://arstechnica.com/news.ars/post/20070...roller-smt.html

  Quote
Gelsinger says that Nehalem cores will support up to two threads, and that the implementation will be "like Hyperthreading." There aren't a lot of details yet, but Gelsinger did say that Nehalem parts would max out at eight cores and 16 threads.

Definitely enable it, Works great with vista, amkes multitasking better, should help a bit with newer games that can take advantage of multithreading. (Hopefully when HL2 Episode 2 comes out hybrid threading will give me a couple fps boost) Makes multitasking better. For some reason when I enabled it in XP it would make apps randomly just "Stop responding" so much that many programs were completely unusable. But in vista it works great and my PC just feels so much more responsive with it on. I can easily Run PS CS3, Firefox with like 40 tabs open, windows media player, and other programs great.

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