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hyperthreading and win2k!

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Spanko

Member
Joined
Aug 3, 2002
Location
Bay Area
on intels website they say to disable HT if your running any windows version other then XP. But it says reccomended, so just to clarify, is HT supported on win2k? will it work?
 

bchur83

Member
Joined
Jan 26, 2003
Location
Land of 10,000 Lakes
I have run HT and win2k before with no problems at all. Some people claim that if you do use HT with win2k, you actually lose performance, but from my experience it works fine and performs better
 

batboy

Senior Moment
Joined
Jan 12, 2001
Location
Kansas, USA
There is another recent thread about this same subject. I'm finding that with Win2k, some benchmarks run faster with HT enabled (like Sandra) and some run slower (like 3Dmark2001). Like Bchur said, my system seems to handle normal multitasking stuff better with HT enabled. That's not scientific, but that is my gut feeling when I have several programs open doing lots of stuff. I know when I'm burning a CD and playing cards on-line, that I have less lag with HT enabled.
 

looktall

Member
Joined
Jul 28, 2002
Location
perth.wa.au
i know this is slightly off topic, but HT will also work with XP home.

this is the closest XP home users can get to having a dual cpu system.
 

TC

Senior Seti Addict
Joined
Jan 15, 2001
Location
Denver, CO
Been running HT under win2k for nearly a year and it runs fine. Big improvement for some apps like Seti.
 

Albuquerque

Member
Joined
Mar 26, 2003
Location
North America
Hyperthreading on Windows 2000 isn't going to make your system blow up, or stop booting, or BSOD. WHat it can and does do under multiple circumstances is make multithreaded single applications (Unreal Tournament 2003 is one such app, so is HALO) run slower.

The multiprocessor HAL in Windows 2000 expects a true multiprocessor system -- multiple physical processors that can do the same exact instructions in parallel. Hyperthreading is not a true multiprocessor function; it can only parallel-task instructions that are unalike: one integer calc, one floating calc. OR one floating calc, one SSE2 calc. OR something of that nature -- it cannot simultaneously process TWO floating point calcs, or TWO integer calcs, etc.

THe difference comes into play when the Windows 2000 multiprocessor HAL starts tasking out a multi-threaded SINGLE application. It's going to cause instruction prefetch misses and actually cause MORE pipeline stalls because the HAL has no understanding that the 2nd "logical processor" isn't a true physical processor that can do ALL instructions at any time.

It doesn't make your machine format itself, it doesn't cause BSOD's (at least, not after SP3 where they fixed that), it won't give you a virus and it doesn't automagically send the pr0n you made with the GF to your mom's email account.

If ALL THAT YOU DO is multitask (burn CD's while surfing while folding or while SETI'ing) then it will likely help to a small extent. If you start playing games, even multiplayer ones, then it's going to start tanking your performance.
 

larva

Inactive Moderator
Joined
Jul 12, 2002
TC said:
Been running HT under win2k for nearly a year and it runs fine. Big improvement for some apps like Seti.
Yes SETI will work fairly well with it, but most other things do not. If you run PCMark, 3DMark2001, or 3d accelerated games of almost any type there is a ~25% performance loss. It's not impossible to find areas where it is not as dismal a failure, but on the whole unless SETI production is your goal you ought turn it off on win2k. Each and every user needs to try it for themselves, but my advice is to turn it off in most situations. And It would surpise me in no small measure if your SETI production on whatever box this is didn't pick up by switching it over to XP.