hyperthreading questions

I'm planning to get a new PC and I have several questions regarding the HT technology:

1. I know that in some, but not all cases that a processor w/ HT technology will be faster than a processor w/o HT technology. But I want to know, for example, will a P4 3.2ghz processor w/o HT outperform a P4 3.2ghz processor w/HT? If so, how could that happen?

2. will it be faster if running several applications using HT than running several applications without HT? Assuming all those applications do not support multithreading

thanks :)
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Hyperthreading is more of a marketing scheme than any real use. In single applications it does not help at all, and infact sometimes causes them to run slower. When multiple applications are used it helps a tiny amount but nothing really significant.

The only p4 processors for sale brand new WITHOUT hyperthreading are called Presscott A's and are only available in 2.4 and 2.8 ghz flavours.

So generally hyperthreading doesnt help much...
Maybe this will be helpfull for you:

Hyperthreading can improve the speed if the application can use multiple prorocessors. In the multimedia world (audio and video encoding) the gain can go up to 30%.

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Did you read what Hyperthreading really is from Intel?

These are the best 3 I could find that you really should atleast look at (if not read all of them)


Intel claims threading an application can result in increased performance on a uni-processor machine or for a multi-processor application. Threads can make a GUI more responsive. They can also facilitate the overlap of I/ O and computation. If multiple processors are available, threaded applications may see substantial speedup.


Threading an existing serial application increases the complexity of the application, Intel says. Sharing of resources, such as global data, can introduce common parallel programming errors such as storage conflicts and other race conditions. Debugging such problems is difficult as they are non-deterministic, and introducing debugging probes, such as print statements, can mask these errors.

Source:http://www.tomshardware.com/cpu/20021227/hyperthreading-01.html (Looks like the next link from Babaloo's Link?)

wlennonVP of Domestic & Int'l OperationsCommented:
I have been using the 3.20 NON HT processor since I built this machine in January.  I run it on as Asus P4800 Deluxe Motherboard with 2gb PC 3200 DDR400 RAM.

When prices dropped dramtically, I got the 3.20 HT Processor and yes it made a difference in my Apps I run, which are mostly Processor intensive.  When you use HT, the system will actually see two processors, you too can see this in the Device Manager.  It isn't a great noticable difference in overall speed until you begin to multi tasking (running serveral Processor intensive programs) then you will see the real difference.

In the upcoming months, software makers are already getting inline to produce their programs to especially gear towards the benifits of HT, some are already available.

There are only 2 P4 HT Processor that have the 90.nm core, and also has a 1mb L3 cache, it is a faster processor due to the fact that all others in the 478 pin catagory are .13u cores with L1 cache 8kb, L2 Cache at 512kb and they come in speeds of

Socket 487 Prescott 3.0E $187.50
Socket 487 Prescott 3.20 $217.50 These are the only 478 Pin Precotts out there w/90nm cores, the rest or Northwood

No offence boxrick, but I thhink you mean Socket T with the Prescott Processors which are smaller, all are .90nm and 775 pin.  There is a list of the Prescotts:


All are 90nm cores, Socket T 775 Pin and they range from:

Prescott 2.8 800 FSB $158.00
Prescott 3.0 800 FSB $177.00
Prescott 3.2 800 FSB $215.90
Prescott 3.4 800 FSB $278.00
Prescott 3.6 800 FSB $435.00

In late 2005 or in 2006, you befing to see dual core Intel Processors, most liley 2006.



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I have run Dual processor computers for a long time now, and I dont think there is a speed difference in the HyperThreaded CPU of the same speed rating at all. The speed comes totally from the computer being smarter about how to do simple tasks. As wlennon stated, you see all the benefits when you multitask. Your clock functions are separated from your Word functions, etc. I do computer graphics quite heavily and the programs I use can use multiple processors, so they definitely benefit from Hyperthreading. The games do not, however, if I am downloading a security update in the background and playing a game, or doing email, etc.. the system has more area to do its "thing". (The intel links above really show that and it does work like that).

It is my opinion though that you are never going to exceed the speed of your hard drives and if you are concerned about speed of your system, I would personally look there first. All of my systems are SCSI based for some silly reason.
skinnypAuthor Commented:
I have found a very good article:


that answer my questions completely.

pts will be given to slaid99 and wlennon as they both mention Processor w/HT is faster when doing multitasking
So my links were useless to you even thought they fully explained your question?
<<pts will be given to slaid99 and wlennon as they both mention Processor w/HT is faster when doing multitasking >>

Thats not 100% accurate just to let u know.
DoTheDEW335... are you referring to the cpu being faster when doing multitasking? If what you say is what I think you mean, then you are correct, its speed will not increase, but it will do its functions faster with decreased overhead. (if that is what you are referring to)
Something not mentioned here, but should be considered... I dont think any Win98 OS'es can actually use Hyperthreading... Not 100% sure on that, but I do know they cant use multiprocessors...so it would stand that Hyperthreading would be a waste on that OS.
wlennonVP of Domestic & Int'l OperationsCommented:
DoTheDEW335, do you use HT Technology?  I can burn a DVD, have AutoCad running in the background, and create a PDF file from PowerPoint at the same time.  Before Hyper Threading, it just wasn't possible, thus my workload productivity has increased near two fold.

It is especially noticeable running two WD SATA Raptor 74gb HDD's in a RAID 0 @10,000 rpm config and a 250 gb SATA @ 7200 rpm as a back up and storage drive.
Yes I do, I have setup over 50 HT machines and 50 Non-HT machines in the last 2 months. If you understand it, then you would know I am correct in this. It depends on the program. Some programs are designed for multiple processors, some aren’t. Those who are not do not generally benefit from HT technology, some have been proven to run a bit slower (although it is rare) and some you do not notice an increase from HT at all. I am a little upset I put any time into this question since I get no acknowledgement from it. My comments and links were ones that described in detail the answer to his question.
<<Before Hyper Threading, it just wasn't possible, thus my workload productivity has increased near two fold.>>

It was possible if you created a PC designed to due these tasks (Duel Processors)
wlennonVP of Domestic & Int'l OperationsCommented:
DEW, I wasn't being sarcastic...I just asked!!

btw- Duel Processor?  (a picture comes to mind to two processors shooting pistols at each other...ROFL)

I do have a server I built with DUAL ZEON processors, I was talking about every day PC's.


Lennon, sarcastic about what?  I never said anything about you being sarcastic. Please re-read my comment. It just states that I had valuable links that pointed out exactly why HT technology is good for certain things and not good for others. I found a great explanation for a question that was asked. I don't feel it was fair that I didn't receive any type of split from this. I take time out of my day to try to help out. I leave few good links and some info and it got thrown out, and that is how I feel. I don't care about my answer getting accepted but I think I deserve an assist, if not I'd like to know why since I feel my comments are a precise answer to the question that was asked.
I have no objection to that at all.
wlennonVP of Domestic & Int'l OperationsCommented:
No problem here.  :)
Thank you , that just made my day :)
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