Dual Processor v. Hyperthreading at DVinfo.net

Stuart Kupinsky · May 28th, 2003, 06:23 PM

Since there is often discussion of the relative merits of dual processors versus single, and the new hyperthreading on the PC side, I thought I would chime in with some recent tests (albeit not the most scientific, I tried to eliminate any variables from the tests but there are a couple, but they're instructive).

I have a dual 2.0GHz Xeon machine running Win2000Pro with 1.5Gig RAM and just purchased a 3.0GHz Hyperthreaded XPPro with 510Meg Ram for my wife. I set up Vegas4 and AfterEffects5.5pro on the new machine with the same plug-ins, etc. I then rendered 3 different projects (1 in Vegas, 2 in AE) on each machine.

Interestingly, the dual processor machine was faster in all 3 tests. It was markedly faster in AE, and somewhat (~10-15%) faster in Vegas. I watched the performance monitor and can only surmise that: (1) the extra memory made a big difference overall; and (2) AE is not hyperthread aware perhaps, whereas Vegas is.

I'll try a little more scientific approach if folks are interested and post times, etc.

John Garcia · May 28th, 2003, 06:36 PM

interesting Stuart. thanks for the feedback. its good to know. Post up more times!

Will Fastie · May 28th, 2003, 10:10 PM

I'm not surprised by this result. I can't recall the exact number, but hyperthreading is like having 1.5 processors, maybe a tad less.

The dual processor system yields about 1.8-1.9 processors (there is some overhead lost to the operating environment).

Following this logic, the Xeons run 1.8 processors in an aggregate 4.0GHz. The P4 runs 1.5 virtual processors in a total of 3.0GHz.

The Xeons should do the work faster.

Nigel Moore · May 29th, 2003, 02:37 AM

I agree with Will. AE renders are CPU intensive and AE is SMP-aware, so your box was faster on the basis of CPU power, not RAM.

Hyperthreading may actually slow a system down in some cases, or so I understand.

What would be really interesting IMO would be a comparison of rendering times with HT enabled and disabled.

Stuart Kupinsky · May 29th, 2003, 05:38 AM

I haven't explored the ability to disable it. I'll look it up (or do you know how?) and try it out.

Nigel Moore · May 29th, 2003, 05:53 AM

HT can be disabled in the BIOS. So it should be possible to do a real-world test on the impact of HT without even opening the box.

Rob Lohman · May 30th, 2003, 07:11 AM

If your bios + Windows fully support Hyperthreading all applications
(unless written to detect HT) will see it as a dual CPU system
instead of single. Or in other words, they will use it the same
way as a dual CPU system. This ofcourse does not mean you
get the same performance increase.

Can you check whether Windows 2000 identifies your processor
as a Hyperthreading processor (it should say so somewhere
in your system properties), because I don't think Windows 2000
supports them out of the box. A later Service Pack (3?) might
have added support for them. This is important because a
OS that doesn't know about Hyperthreading will not gain any-
thing by having it!! Also your BIOS must have it enabled as
pointed out above.

Nigel Moore · May 30th, 2003, 09:44 AM

Quote:

If your bios + Windows fully support Hyperthreading all applications
(unless written to detect HT) will see it as a dual CPU system
instead of single. Or in other words, they will use it the same
way as a dual CPU system. This ofcourse does not mean you
get the same performance increase.

In fact, the few tests that I've seen on the web suggest a marginal improvement at best. But they've fallen short of being exact comparisons. Which is why I asked Stuart to run tests on his wife's system with HT on and off. Without changing any other parameters, it should give an idea of what HT really can do...beyond the hype

Quote:

Can you check whether Windows 2000 identifies your processor
as a Hyperthreading processor (it should say so somewhere
in your system properties), because I don't think Windows 2000
supports them out of the box.

W2K does not support HT. But his wife's system, which has the HT processor, runs XP, which does support HT. It's unlikely that Stuart's dual Xeons in his W2K workstation are HT, so the fact that W2K doesn't support this technology is moot.

Rob Lohman · June 2nd, 2003, 09:46 AM

I must have mixed up the OS-es... Sorry. I know for sure I once
saw a Windows 2000 Server machine identifying a processor
as a HT processor. Perhaps there was a special extension
installed or something.

May 28th, 2003, 06:23 PM	#1
Stuart Kupinsky Regular Crew Join Date: Jul 2002 Location: Princeton, NJ Posts: 82	Dual Processor v. Hyperthreading Since there is often discussion of the relative merits of dual processors versus single, and the new hyperthreading on the PC side, I thought I would chime in with some recent tests (albeit not the most scientific, I tried to eliminate any variables from the tests but there are a couple, but they're instructive). I have a dual 2.0GHz Xeon machine running Win2000Pro with 1.5Gig RAM and just purchased a 3.0GHz Hyperthreaded XPPro with 510Meg Ram for my wife. I set up Vegas4 and AfterEffects5.5pro on the new machine with the same plug-ins, etc. I then rendered 3 different projects (1 in Vegas, 2 in AE) on each machine. Interestingly, the dual processor machine was faster in all 3 tests. It was markedly faster in AE, and somewhat (~10-15%) faster in Vegas. I watched the performance monitor and can only surmise that: (1) the extra memory made a big difference overall; and (2) AE is not hyperthread aware perhaps, whereas Vegas is. I'll try a little more scientific approach if folks are interested and post times, etc. __________________ DVX100A/AT4071a/Vegas/After Effects Dual 2GHz Xeon PC

May 29th, 2003, 05:38 AM	#5
Stuart Kupinsky Regular Crew Join Date: Jul 2002 Location: Princeton, NJ Posts: 82	I haven't explored the ability to disable it. I'll look it up (or do you know how?) and try it out. __________________ DVX100A/AT4071a/Vegas/After Effects Dual 2GHz Xeon PC

May 30th, 2003, 07:11 AM	#7
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	If your bios + Windows fully support Hyperthreading all applications (unless written to detect HT) will see it as a dual CPU system instead of single. Or in other words, they will use it the same way as a dual CPU system. This ofcourse does not mean you get the same performance increase. Can you check whether Windows 2000 identifies your processor as a Hyperthreading processor (it should say so somewhere in your system properties), because I don't think Windows 2000 supports them out of the box. A later Service Pack (3?) might have added support for them. This is important because a OS that doesn't know about Hyperthreading will not gain any- thing by having it!! Also your BIOS must have it enabled as pointed out above. __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

June 2nd, 2003, 09:46 AM	#9
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	I must have mixed up the OS-es... Sorry. I know for sure I once saw a Windows 2000 Server machine identifying a processor as a HT processor. Perhaps there was a special extension installed or something. __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

May 28th, 2003, 06:36 PM	#2
John Garcia Regular Crew Join Date: May 2003 Location: Honolulu, Hawaii Posts: 199	interesting Stuart. thanks for the feedback. its good to know. Post up more times!

May 28th, 2003, 10:10 PM	#3
Will Fastie Major Player Join Date: Feb 2003 Location: Jarrettsville, MD Posts: 353	I'm not surprised by this result. I can't recall the exact number, but hyperthreading is like having 1.5 processors, maybe a tad less. The dual processor system yields about 1.8-1.9 processors (there is some overhead lost to the operating environment). Following this logic, the Xeons run 1.8 processors in an aggregate 4.0GHz. The P4 runs 1.5 virtual processors in a total of 3.0GHz. The Xeons should do the work faster.

May 29th, 2003, 02:37 AM	#4
Nigel Moore Major Player Join Date: May 2003 Location: Switzerland Posts: 358	I agree with Will. AE renders are CPU intensive and AE is SMP-aware, so your box was faster on the basis of CPU power, not RAM. Hyperthreading may actually slow a system down in some cases, or so I understand. What would be really interesting IMO would be a comparison of rendering times with HT enabled and disabled.

May 29th, 2003, 05:53 AM	#6
Nigel Moore Major Player Join Date: May 2003 Location: Switzerland Posts: 358	HT can be disabled in the BIOS. So it should be possible to do a real-world test on the impact of HT without even opening the box.