Results 1 to 12 of 12

Thread: Windows Xp and HyperThreading

  1. #1
    Bronze Member Rex Mundi's Avatar
    Join Date
    Apr 2004
    Location
    The Netherlands
    Posts
    121

    Windows Xp and HyperThreading

    Okay this may sound really dumb, but isn't at all very obvious. You just got a P4 with HyperThreading. Well that sounds good. Then you realise you have to enable HyperThreading in the BIOS. Okay, done that and you start windows. When you press ctrl-alt-del you go to the Task Manager and in the tab 'Performance' you suddenly see 2 windows displaying cpu activity. "Hurray, its working," you think aloud. Then you eventually realise that both windows show the same cpu activity no matter what programmes you execute "How can this be? Is this how HT is used effectively or what?"

    What windows doesnt tell you is that for every programme you can set 1 or both virtual processors, thereby making effective use of HT. How to do it? I just found out today...

    See the attached screenshot how to find the "hidden function"
    Get Quintessential player, the alternative to winamp! ( www.quinnware.com )

  2. #2
    Super Moderator Super Moderator Big Booger's Avatar
    Join Date
    Apr 2002
    Location
    JAPAN
    Posts
    10,941
    I just took a look and my CPU Usage History is not the same.. in fact, each line is quite different. One seems higher than the other and I haven't touched the process affinity.

  3. #3
    Bronze Member Rex Mundi's Avatar
    Join Date
    Apr 2004
    Location
    The Netherlands
    Posts
    121
    Im not saying that without making use of 'process affinity' HyperThreading doesnt work, but that it may work less efficient. For example, i use folding @ home, a programme that eats a lot of cpu cycles by doing complex computations. If i set this application to CPU0 (ignoring the fact that it has a low priority) and some of the other applications that i frequently use to CPU1, then this surely must be more efficient, ie that my computer shouldn't slow down.

    Another example is using a video compression programme on one CPU and playing a 3d game the other cpu. The computer shouldnt slow down this way, but i guess you know this already.
    Get Quintessential player, the alternative to winamp! ( www.quinnware.com )

  4. #4
    Super Moderator Super Moderator Big Booger's Avatar
    Join Date
    Apr 2002
    Location
    JAPAN
    Posts
    10,941
    Now I see what you mean. Yeah that makes sense. Dedicating one virtual CPU to a specified task and another to another.

    Gotcha.

  5. #5
    Techzonez Governor Super Moderator Conan's Avatar
    Join Date
    Apr 2002
    Location
    Philippines
    Posts
    4,343
    Quote Originally Posted by Rex Mundi
    Okay this may sound really dumb, but isn't at all very obvious. You just got a P4 with HyperThreading. Well that sounds good. Then you realise you have to enable HyperThreading in the BIOS. Okay, done that and you start windows. When you press ctrl-alt-del you go to the Task Manager and in the tab 'Performance' you suddenly see 2 windows displaying cpu activity. "Hurray, its working," you think aloud. Then you eventually realise that both windows show the same cpu activity no matter what programmes you execute "How can this be? Is this how HT is used effectively or what?"

    What windows doesnt tell you is that for every programme you can set 1 or both virtual processors, thereby making effective use of HT. How to do it? I just found out today...

    See the attached screenshot how to find the "hidden function"
    I just checked mine and most of my apps are already set like that screenshot of yours.

  6. #6
    Old and Cranky Super Moderator rik's Avatar
    Join Date
    Aug 2003
    Location
    Watching Your every move...
    Posts
    4,688
    Good thread Rex Mundi...

  7. #7
    Junior Member
    Join Date
    Sep 2004
    Posts
    1
    I've got a question then. Most of the programs I have running that are somewhat system hogs. or that are always running (virus scanner, firewall, etc) are started as system processes. If I try and change the affinity on them I get an "access is denied" error. How can I restrict those to just run on a specific virtual CPU?

  8. #8
    Titanium Member Tinker's Avatar
    Join Date
    Apr 2002
    Location
    Indiana U.S.A.
    Posts
    1,064
    Very nice Rex Mundi. I have just set the items that allows me to so the apps alter back and forth on CPU usage.


  9. #9
    Bronze Member Rex Mundi's Avatar
    Join Date
    Apr 2004
    Location
    The Netherlands
    Posts
    121
    Baka, you probably need administrator privileges in order to change the affinity of certain programmes. Else, i have no idea.

    Something else, when you reboot windows, everything is restored to default settings and you have to re-apply the affinity of certain programmes to a certain CPU. I recently noticed. Kinda shows how annoying microsoft is; ie for everything anything reverts back to the default settings including ms office.
    Get Quintessential player, the alternative to winamp! ( www.quinnware.com )

  10. #10
    Junior Member
    Join Date
    Mar 2005
    Posts
    5
    HT works faster with latest version of windows.
    So if u r using XP try to update it for better performance.

  11. #11
    Security Intelligence TZ Veteran cash_site's Avatar
    Join Date
    Jul 2002
    Location
    Software Paradise
    Posts
    3,852
    Quote Originally Posted by atre123
    HT works faster with latest version of windows.
    So if u r using XP try to update it for better performance.
    Thats right, SP2 was optimized for HT and handles varying CPU loads better with internal management of Affinity... on two same PCs with same HD images expect one is plain XP other is SP2, SP2 handles multithreaded programs way better and sets its own affinity... it will max out 1 CPU which is 50% overall and other will be used for 'foreground' processes

    Definitely a move to SP2 will aide performance issues...

    --- 0wN3D by 3gG ---

  12. #12
    Junior Member
    Join Date
    Dec 2005
    Posts
    1

    ht not working right

    Ok I just reinstalled windows xp and all of the updates. I checked and ht is enabled in the bios. My problem is everytime I install a program or a program requires a restart, the hyperthreading is turned off. It is only enabled if I do a shutdown and then restart it. Is there a way to prevent it from being disabled if I just do a restart?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •