View Full Version : P4, hyperthreading and W2K/XP, is it useful?

03 March 2003, 02:02 PM

having just uppgraded, to a new mobo(asus with e7205 chipset) & CPU, mobo supports hyperthreading, not sure if the cpu (a P4 2.4 533) does, question is after reading throuhg the docs that came with mobo which says that XP is the OS to be used for hyperthreading, does it make any difference performace wise? I mean is it some crap like MMX was or is it actually useful?

Personally I would rather go with w2k since I really dont like all the mickey mouse stuff going on in XP(no offense to Mickey mouse though), or better still use NT4, but thats not a option since it's seems that the support for NT4 is going out of fashion fast, and if this hyperthreading makes a differnce how cold one tell if the cpu does support it?


Christian Mir
03 March 2003, 02:28 PM
Hi Slugger,

The first P4 which supports HT is the 3.06Ghz, so you would have to upgrade your processor in order to use it.

Basically HT will help you with multithreaded software and with multitasking.

Greg Hess from 3dluvr is producing a very thorough benchmark using HT with several 3d softwares. Take a peak at on the benchmarking section...

I hope it helps.

03 March 2003, 03:19 PM
Ok Christian,

thanks, had a look, seems that its both good and bad things with this new hyperthreading, but lucky as I am have not have to deal with either (at this time) since I have a 2.4!


03 March 2003, 06:31 PM
I believe that Hyperthreading is NOT supported in W2K, only in W2K Advanced Server.

It is fully supported in Win XP though.

03 March 2003, 01:32 AM
Hyperthreading will work in Win2k Prof, but only with a single cpu. (Aka you can't run Dual Xeon's in win2k with HT enabled. It won't work to its full capacity).

Ditto on what lee said on the os's.

03 March 2003, 02:48 AM
Do they make XEON's with HT?

Or are you saying that you can run 3.06's in a dual config?

03 March 2003, 03:10 AM
all pentium 4 based xeon chips are HT capable. in my office i have dual 1.8GHz, dual 2.0GHz, dual 2.2GHz and dual 2.8GHz xeons, all running hyper threading under windows XP professional.

as greg mentioned, windows 2000 cannot tell the difference between real and virtual processors. as such, turning on HT under win2k with dual xeons will not work, as the system sees 4 cpus, and win2k is limited to 2 cpus per license. for dual xeons under win2k, you must use win2k server or advanced server. single CPUs running HT is not a problem, as win2k sees 2 cpus which are still within license.

windowsXP however does see the difference between real and virtual cpus, so dual xeons under winXP pro with HT turned on will correctly show the "4 cpus" in task manager.

03 March 2003, 03:58 PM
I'm wondering though, would a Xeon system with HT enabled (4procs) see a speed increase over the same system with HT disabled (2procs), due to memory bandwidth limitations? (under XP).

Asking because I am comtemplating moving a dual Xeon system to XP, and wondering if i will actually gain anything over 2K.

03 March 2003, 04:09 PM

Under Vray, (, there is a 20-25% PERFORMANCE INCREASE moving to Windows XP from Win2k, with Hyperthreading enabled. Vray/Brazil use a bucket rendering system, which allows each logical cpu to be assigned a portion of the scene. (4 Buckets under XP with HT enabled, as opposed to 2 under win2k). This really maximizes the potential of HT to an extreme level.

Under Max5, the % is significantly smaller, as discreet's renderer doesn't allow for efficent scaling past 2 cpu's. (Its about 6% faster).

It should be known, that a 25% performance increase is larger then...

1) Switching between DDR, Rambus, or DC-DDR
2) Switching between 400 and 533 FSB chips.
3) Switching between a dual 2.6 xeon and a dual 2.8B Xeon. (With HT disabled)

Needless to say, its a massive difference.

Lightwave is showing around a 10% diffy depending on which scene you choose.

I haven't had a chance to do maya/xsi yet.

03 March 2003, 04:26 PM
Seems a switch to XP may be in order, keeping the interface in Win2K mode, mind you... ;)

03 March 2003, 04:30 PM
Ya thats what I do. If you disable everything in Windows XP, you basically get win2k with HT Support. There is a utility, (Tweak XP) I believe that allows you to shutoff even more functions.

Its actually possible to get XP around the same ram usage as 2k. You just have to disable everything that makes it XP :).

03 March 2003, 04:35 PM

Seeing how the XP switch appears imminent...any "off the top of your head" tips for keeping XP lean I'll check Tweak XP after installing...

03 March 2003, 05:23 PM
Set everything to class mode.

Disable active desktop.

Disable auto restore.

Under ctrl panel, system-advanced, performance

Set to maximum performance.

Under display properties/effects disable everything but cleartype font.

There are also about 20 services you can disable.

03 March 2003, 05:38 PM
Originally posted by visualboo
Do they make XEON's with HT?

Or are you saying that you can run 3.06's in a dual config?

I have at work a web server with dual Xeons 2.5 or something with HT the server identifies 4 processor.. hooo.. if they let me use that baby for rendering :bounce: :shrug: , but they don't :thumbsdow

03 March 2003, 11:31 PM
Ah, thanks guys. I thought the HT was new for the 3.06. I'm deffinitely upgrading from this crap ass 2600xp

AMD :thumbsdow

03 March 2003, 02:44 AM
Hey VB,

Intel will also be adding HT to their P4 line (other then the 3.06) in the future. Just the only P4 chip with HT available now, is the 3.06.

Remember that Xeon's are not P4's, as they follow a different socket format. (603 for the old ones, 604 for the new. P4's are Socket 478).

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