Hyperthreading

dave_0273 · 2003-12-11, 23:38

I have a P4 2.4Ghz with a gig of ram. However I am running windows 2000 and have heard that as far as prime95 goes, i am only running at about 50% of my computers capacity. Is this true???

I was also wondering if someone could explain in detail how to turn hyperthreading off so that i can get the best out of my computer.

nfortino · 2003-12-11, 23:53

This is discussed in the two threads below:
http://www.mersenneforum.org/showthr...hyperthreading
http://www.mersenneforum.org/showthr...hyperthreading

As near as I can tell, Prime95 is actually tacking all cycles, but the task manager only sees it as 50%

GP2 · 2003-12-12, 01:04

I believe that some other threads have stated that Windows 2000 doesn't handle hyperthreading properly... the slowdown is real. Best to disable hyperthreading in the BIOS. On other operating systems like Win XP, some programs report 50% but in fact there is no real slowdown.

xtreme2k · 2003-12-12, 06:51

I have typed this for the 1349823948235th time :)

Win2k DOES NOT SUPPORT HT. It does 'work' but it doesnt work at full speed. Try enable/disable and do a benchmark within prime and you will see having it disabled in Win2k is much faster.

However WinXP fixed this problem.

dave_0273 · 2003-12-12, 11:48

xtreme2k:- could you please explain to me (in as much detail as you can bear) how exactly to turn hyperthreading off. I have been told "in the BIOS" but being a complete newbie myself, i have no idea what this means.

TauCeti · 2003-12-12, 13:22

I try a simple explanation:

When you switch on your computer, at first the BIOS is active and then your Windows 2000 is loaded.

Depending on your motherboard, you have to press a special key (usually the 'Del' Key) to enter the BIOS-Setup. There may even be a message on your screen during bootup telling you what key to press. Or you can look in the documentation of the motherboard of your computer.

If you will give it a try without looking in the documentation (although _i_ would look into it) you can power down your computer and then switch it on again. Start pressing the "DEL" key in short intervals (about 1 second).

If Windows 2000 boots, you did not make it - otherwise you should see the BIOS-Setup.

In this Setup there are a lot of options and sub-menus. Somewhere should be an entry "HT-support" or "Hyperthreading" Switch this from "ON" to "OFF", leave the Setup with saving and you disabled Hyperthreading in the BIOS.

If you accidently change some other values in the BIOS-Setup or become confused, leave the menu without saving.

hth

2003-12-11, 23:38	#1
dave_0273 Oct 2003 Australia, Brisbane 2×5×47 Posts	Hyperthreading I have a P4 2.4Ghz with a gig of ram. However I am running windows 2000 and have heard that as far as prime95 goes, i am only running at about 50% of my computers capacity. Is this true??? I was also wondering if someone could explain in detail how to turn hyperthreading off so that i can get the best out of my computer.

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2003-12-11, 23:53	#2
nfortino Nov 2003 3·5·11 Posts	This is discussed in the two threads below: http://www.mersenneforum.org/showthr...hyperthreading http://www.mersenneforum.org/showthr...hyperthreading As near as I can tell, Prime95 is actually tacking all cycles, but the task manager only sees it as 50%

2003-12-12, 01:04	#3
GP2 Sep 2003 2×5×7×37 Posts	I believe that some other threads have stated that Windows 2000 doesn't handle hyperthreading properly... the slowdown is real. Best to disable hyperthreading in the BIOS. On other operating systems like Win XP, some programs report 50% but in fact there is no real slowdown.

2003-12-12, 06:51	#4
xtreme2k Aug 2002 174₁₀ Posts	I have typed this for the 1349823948235th time :) Win2k DOES NOT SUPPORT HT. It does 'work' but it doesnt work at full speed. Try enable/disable and do a benchmark within prime and you will see having it disabled in Win2k is much faster. However WinXP fixed this problem.

2003-12-12, 11:48	#5
dave_0273 Oct 2003 Australia, Brisbane 2×5×47 Posts	xtreme2k:- could you please explain to me (in as much detail as you can bear) how exactly to turn hyperthreading off. I have been told "in the BIOS" but being a complete newbie myself, i have no idea what this means.

2003-12-12, 13:22	#6
TauCeti Mar 2003 Braunschweig, Germany 2×113 Posts	I try a simple explanation: When you switch on your computer, at first the BIOS is active and then your Windows 2000 is loaded. Depending on your motherboard, you have to press a special key (usually the 'Del' Key) to enter the BIOS-Setup. There may even be a message on your screen during bootup telling you what key to press. Or you can look in the documentation of the motherboard of your computer. If you will give it a try without looking in the documentation (although _i_ would look into it) you can power down your computer and then switch it on again. Start pressing the "DEL" key in short intervals (about 1 second). If Windows 2000 boots, you did not make it - otherwise you should see the BIOS-Setup. In this Setup there are a lot of options and sub-menus. Somewhere should be an entry "HT-support" or "Hyperthreading" Switch this from "ON" to "OFF", leave the Setup with saving and you disabled Hyperthreading in the BIOS. If you accidently change some other values in the BIOS-Setup or become confused, leave the menu without saving. hth