Does XP Pro directly support 2 processors?

[TroyMcClure]

If I get a dual processor board, and have XP Pro as the OS, can I expect to be able to run 2 apps, each running full out with it's own processor?

For example, let's say I have a video capture program and a video editing program. On my current box, a P4 with 1 gig ram, the video capture will just barely collect 30 fps mpeg video from a camcorder or capture device just fine with no dropped frames. But if I run another app--even low-bandwidth apps--at the same time, I'll drop some frames. Basically I'm right at the edge of the envelop. Then, afterwards, I run the editing/rendering program and let's say it takes x amount of time to render an hour of video.

Now, with a dual-p4 system with 2gig ram, could I capture video and edit another bit of video at the same time--each not missing a beat? Ie, the capture still not dropping frames, and the render still taking the same x amount of time (within reason because I know there's a little overhead)?
Thanks,
--T

 

[rvnguy]

TroyMcClure,

Video Capture is such a touchy area that I would not go out on a limb and say that with dual proc's you could perform two at the same time with out a dropped frame.

While there are two proc's there is only one FSB and single other items. This process is not fully contained to the proc, it must access additional info over the bus and therefore there could and most probably will be problems. Dual proc's is not exactly like having two discreet machines.

It is not a basic OS problem, but one of shared resources, i.e. PCI bus, FSB, mem I/O, etc. And from the information that I have seen, the Capture apps are possibly not tolerant of multi-processing environments.

Now for other than Video capture and or other highly I/O intensive applications, this is a viable solution and XP64bit promises to be even more robust once drivers are developed.

Hope this assists in clarifying



rvnguy
"I know everything..I just can't remember it all

 

[smah]

The OS can make full use of both processors, but many software applications can not.

 

[Frank4d]

Now, with a dual-p4 system with 2gig ram, could I capture video and edit another bit of video at the same time--each not missing a beat? Ie, the capture still not dropping frames, and the render still taking the same x amount of time (within reason because I know there's a little overhead)?

No... not without software specially written to take advantage of the two CPUs.

 

[Nelviticus]

I don't think Frank4d is completely correct. As I understand it:

- The standard Windows XP licence supports up to two actual processors or two cores, so if you got a dual-core or dual-CPU motherboard your current licence would support it;
- A dual core or dual CPU machine will happily run separate applications on each CPU/core even if they're not specifically designed for dual CPU/core;
- For an individual application to benefit from a dual CPU/core setup it has to be specifically written to support it.

What that means is that if you have a dual machine and you run a single application, it will run no faster than on an equivalent single-CPU machine. However if you start a second application while the first one is chugging away, it will take advantage of the second CPU and run almost as fast as if you were only running one application (subject to sharing system resources as mentioned by RvnGuy).

However if you run a single application that does a lot of things at once - say adding an effect to one video stream while re-sizing another - unless it's designed specifically to take advantage of dual CPUs it will not run any faster on a dual-CPU machine.

So to answer your original question - yes, if you run a video capture application and a separate video processing application at the same time, they will run a lot faster on a dual-core or dual-CPU machine. Neither will run quite as fast as they would if you ran them one at a time because they will both be sharing the same hard drives, memory and so forth, as described by RvnGuy.

Regards

Nelviticus

 

[bcastner]

Processor affinity is adjustable:

http://www.tomshardware.com/cpu/20040528/task-assignment-01.html

Let me correct this statement by Nelviticus:

- The standard Windows XP licence supports up to two actual processors or two cores, so if you got a dual-core or dual-CPU motherboard your current licence would support it;

This implies that if you had two dual-core processors, your license would not support it. XP's license supports this and would show four processors.

 

[Nelviticus]

Aha. Does that apply to all XP licences? Reading the licence sticker on my box here at work it says "Windows XP Professional 1-2 CPU". I assumed that a 'virtual' CPU as found in a dual-core processor would be treated the same as a real one for licence purposes - I was obviously wrong!

Nelviticus

 

[bcastner]

http://www.microsoft.com/licensing/highlights/multicore.mspx

 

[TroyMcClure]

Thanks everyone very much. Since the Capture and Editing apps are seperate, I should be able to enjoy at least some gain. I understand about the sharing of the bus, etc, and also about a single app not necessarily being written to put different threads on different cpus--but as long as the OS can put different apps on different CPU's, then I'm fine.

I'm thinking that the editing will be largely cpu/memory intensive, while capture will use the io bus and harddrive.

Now...off to the 'board shop' to see what I can get...
--T