Benefit of HyperThreading?

Discussion in 'Intel x86 CPUs and chipsets' started by dcl, Oct 2, 2009.

  1. dcl

    dcl Member

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    Hey guys, I'm putting a new rig together very shortly and am wondering which CPU I should get out of the i5 750 or i7 920 (or even the i7 860)

    Basically as I see it they pretty much all have pretty similar performance, but the 920 has a weaker turbo mode, triple channel ram, hyper threading and easier to o/c.

    The 750, cheaper, no HT, dual channel, etc.

    The difference in memory bandwidth doesn't bother me, although I do a lot of stats, I don't think it would make too much difference. (Actually, a benchmark in the R stats environment would interest me a great deal, haha)
    Turbo mode doesn't bother me too much either as I plan on o/c'ing.

    I don't think I'll be doing too much video encoding and rendering so HT won't benefit me much there, and games don't really make use of it. In fact am I right in saying sometimes they perform better with it disabled?

    Now given in games and number crunching the CPU's offer relatively similar performance (depending on the app) am I going to 'want' HT? In the real world and for everyday use, where I have 2 screens with 11ty apps open, does HT make a difference? I think when the new i5 chips came out, [H] said windows didn't feel as 'snappy' due to the lack of HT, would anyone agree with this?

    All thoughts welcome. :)
     
  2. Autti

    Autti Member

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    Hyper Threading makes the biggest difference in simple algorithms to compute, i.e superPI, i assume you mean statistical mathematics? Which would probably see quite a benefit from hyper threading. Hyper threading often decreases game performance, but isn't noticed with i7's because they are so fast without it anyway.

    It will just come down to cost, for most programs hyper threading will be faster, but more expensive. The 920 is quite a step up from the 750, but the 750 certainly isn't slow. Also consider most 920 setups have 2 PCI-e 16x support making future graphics card scaling better.

    The 920 is probably better bang for your buck though, considering it can be quite cheap now that would be my option for an upgrade, the 750 is of course cheaper, but 860 is just a few dollars less than a 920 and its worth spending the extra cash for that performance IMO.
    Go 920 if u want speed but a little more expensive only $250 or so. Or 750 if u want a budget build.
     
  3. Thrawn

    Thrawn Member

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    Also consider that enabling HT generally makes the CPU a good deal hotter (by as much as 5 to 10 degrees C)
     
  4. slickncghia

    slickncghia Member

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    i think ht is a bit overrated. but thats just my biased opinion.
     
  5. OP
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    dcl

    dcl Member

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    Hmmm, that is indeed what it will probably come down too.

    I plan on getting a 5850 and having the P55 with the nerfed secondary PCIe slot doesn't bother me too much. Apparently it's a max of just a few % slower with a second card in there compared to two 16x slots.
     
  6. OP
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    dcl

    dcl Member

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    Aside from HT, do you guys see any point in going for the 920 over the 750? Besides the extra PCIe lanes?

    I'm not going to notice the difference in memory bandwidth. :o Though the platform does give me the choice between 4/8 or 6gb of ram.
    Running 4gb here at uni, and can't imagine having less at home.
     
  7. OP
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    dcl

    dcl Member

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    Perhaps what I'm most concerned about: :Paranoid: But it's probably just rubbish?

    http://hardocp.com/article/2009/09/07/intel_lynnfield_core_i5_i7_processors/6


    Plan on getting an SSD, want everything to be lightning quick. :o
     
  8. DarkForceMage

    DarkForceMage Member

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    During the day my cpu idles around 35 since the hot weather started, doesnt help that I live in a garage where the ambient temp is hotter than outside, my temps never go above 65 and thats with an easily achieved 3.6ghz OC. At night time its more around 32c idle, 55 load.

    To me the biggest difference from switching from a core2quad rig to i5 was the fact it has the on-die memory controller, hyperthreading & triple channel isnt a big deal to me because the premium isnt worth it, as I'v heard alot of people turn off HT for stability and temps anyway.

    I guess if your rich AND you overclock i7 is a good way to go but if you like value for money I would go with i5.

    The best example I can think of is one of my mates who isnt too computer saavy, he knows about the different parts & how to build a PC but he doesnt dabble in tweaking or OCing at all.

    He bought a custom i7-920 oc'd to 3.2ghz setup with triple channel ram and a GTX 285 + monitor etc for about $2500, thats at least $1900 on the tower alone.

    My i5 rig smokes his in superPI and real world apps(gaming etc.) although his wins with memory bandwidth it doesnt really make him feel any better lol.

    Oh and I havent even started on how easy it is for me to OC upto 4.2ghz but I'm not gonna run that as a 24/7 OC til something actually needs that kind of power.

    If I had to choose again and was given enough money for an i5 or i7x58 rig I would still choose i5, I would still get an i5-750 and I would spend the extra money on a high end SSD, because if anything, that would make the comp seem "snappiest"
     
  9. slickncghia

    slickncghia Member

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    920 has a higher number? future proofing socket blah blah blah ect.

    buy what you need dont waste money on stuff you dont need and wont make a difference for you
     
  10. OP
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    dcl

    dcl Member

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    Indeed DFM, and I tend to agree with you (having personally used neither systems!)
     
  11. OP
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    dcl

    dcl Member

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    wisdom.


    :leet:
     
  12. mAJORD

    mAJORD Member

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    The Hyperthreading decision is pretty simple really. Its effect is essentially adding an extra core or 2. Nothing more to it.. If the app would make use of extra cores, then it (in most cases) would make use of HT.

    Only complications are as mentioned, it can hinder performance in SOME games, and the occasional app
     
  13. terrastrife

    terrastrife Member

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    wait what? no, it only lets the cpu use unused bits of itself. ht is not another core and quite often stuffs up many non smp but multi core programs.

    hyperthreading is great for apps that use it.. the only app i can think of that works with HT well, is Windows. so if yorue cranking at full 100% cpu usage, with HT explorer.exe is still quite responsive as the unused pipelines are more than enough for explorer to function.
     
  14. OP
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    dcl

    dcl Member

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    But in reality, do you feel a difference in windows?
     
  15. mAJORD

    mAJORD Member

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    I'll emphasize what I said..

    Its Effect (performance wise) is that of an extra core.

    I didn't say it WAS an extra core.

    It's appearance to the operating system, and Applications is that of an extra 4 cores ( so an 8 core CPU)

    You're correct in that it's inner workings allow it to use "unused bits" of the CPU.. (execution resources). All this is completely "behind the scenes", and transparent to the operating system though, it see's 8 threads. and when an app uses all those 8 threads, the end performance is that of around 5 threads or so..
     
  16. 3Tone

    3Tone (Banned or Deleted)

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    What about hypervisors? VMware, Hyper-V, Xen etc?
     
  17. Autti

    Autti Member

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    just get a 920, its can only be $300 more than a i5 750, $100 for the CPU and $150 odd for the motherboard, RAM prices are the same. 920 is faster and worth the extra. Dont bother about 860 atm its to expensive and isn't quick enough to justify the price.
     
  18. DarkForceMage

    DarkForceMage Member

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    Isn't quick enough? Depends,, theres not that many things that push an i5 - 750 OR an i7 - 920 rig.
     
  19. OP
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    dcl

    dcl Member

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    Don't most benchmarks put the 860 ahead of the 920?
     
  20. Autti

    Autti Member

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    Stock it does, but the 920 overclocks better and will perform ahead when both are overclocked.

    The thing is, hyper threading isn't really worth it, it doesn't improve gaming, makes windows slightly snapier,prime will run faster and so will superPI. But the price difference between a 920 and 750 is so little, its worth get the 920 just for the overclocking headroom and with HT turned of the speed benefits.
    Of course this is assuming u can spend another $300 which a lot of people couldn't afford.
     

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