dual processor boards?

[e_storm]

Pardon the basic question, but if you run a dual board with, say, 2 pIII 800s, will you actually be running at 1.6ghz? And what are they usually used for? Servers and stuff, or just hard core gamer machines? The reason I ask is because instead of having to upgrade your board every time the new, faster CPUs come out that go past the capabilities of your board, why not just get a dual board with a limit of say 1 gig per chip which would put you at a limit of 2 gigs? Seems like it would give you more room to upgrade speed without replacing the board all the time. Am I way off here?

 

[DaveB]

Yeah you are off the mark here. Most apps can only use one processor, so the second one is just a space heater. Plus, in order to distribute normal processing across two CPUs you need to be running a dual-capable OS, such as Win 2K, which implements Symmetric Multiprocessing (SMP). You could then be running two programs simultaneously under SMP, for example, one on each CPU. But each is only running at the speed of the individual CPU, and are sharing RAM, the hard drives ,and other motherboard resources. So you'll never get an effective 2x processing throughput.

Then there’s multithreading, which allows a single program to use multiple processors. A multithreaded application must be specifically written to execute tasks in parallel across multiple processors. Such programs must include scheduling to keep the various threads in sync. An example of a common multithreaded application that can use multiple processors is Quake 3 Arena. Multithreaded apps do not require SMP and can therefore work even under Win 98. But writing such programs is very labor intensive and there aren’t enough dual CPU rigs out there for this to become commonplace. BEOS is an OS that automatically multithreads all applications on its own. But it’s not gonna suddenly take over the world from Microsoft.

There’s a lot more to this, but you get the idea. Even under ideal conditions, running two 800 MHz CPUs will not give you an effective 1.6 GHz system. And most OS’s and applications can’t make use of the two CPUs anyway. I’m no expert here, so if someone want’s to enhance or correct any of these, please do.

 

[Tim-]

You pretty much nailed it! When running an SMP capable operating system, the second cpu does serve a purpose. It takes care of housekeeping and background services that would otherwise have to be time-sliced by the main cpu. This results in a gain of 5-10% in speed over a single cpu system. This is pretty negligible though, and doesn't impact operations very much. Even multithreaded applications typically only show a 35-50% increase in speed using SMP.

SMP machines shine when it comes to multitasking, and that is why they are commonly used as servers- in workstation service they are limited as described above. With good multithreaded software, the increase in performance is very real and for tasks such as CAD, graphic arts, and video editing they work very well. Unfortunately very few applications are multithreaded, and they are typically the high dollar programs. AutoCAD, 3D Studio, Maya 3D, Photoshop, and Adobe Premier are among the most common multithreaded applications.

 

[William]

unless its a server or heavy digital editing with sound, video, or photoshop type stuff, stick with a single CPU. Every OS using SMP is MORE UNSTABLE than when it uses one. Even Linux and BeOs are more unstable with SMP.

 

[Tim-]

I can't say that I have seen that. It's true that you can't run dual cpus as fast (per cpu) as they will often run on a single cpu MB. All of my machines, including 2 VP6/PIII-700 @1GHz machines are as stable as any I have ever seen. They are running variants of W2000 and have never crashed the OS, even after several months of 24/7 operation. During the same time I don't think I have seen more than one or two applications crash either. My single PIII-700@1050MHz is also very stable, but no more so than the dualies.

 

[[OC]_SR20DE]

Also.. I need confirmation about the Dual processor and a Single processor in gaming performance. It is true that you will not gain much of performance on... let say .. Dual P3 500 over a Single P3 500 system.. right?


The Duals are more for overall office apps where they can do more amount of work load(multi-tasking), whereas the single 1Ghz system does one thing at a time but at its rated 1ghz speed.. right? Tim, I need your input or anybody else welcome(if you know) =0

 

[Kryten]

E_Storm (Apr 11, 2001 07:30 a.m.):
Pardon the basic question, but if you run a dual board with, say, 2 pIII 800s, will you actually be running at 1.6ghz? And what are they usually used for? Servers and stuff, or just hard core gamer machines? The reason I ask is because instead of having to upgrade your board every time the new, faster CPUs come out that go past the capabilities of your board, why not just get a dual board with a limit of say 1 gig per chip which would put you at a limit of 2 gigs? Seems like it would give you more room to upgrade speed without replacing the board all the time. Am I way off here?

Don't think I could add much more then DaveB and Tim have already said, it comes down to horses for courses, If you use your machine for any of the above programs and your running an OS that is based on the NT kernel e.g. Win 2000 (all versions) then go for it but if your just using run of the mill single user programs and don't play anything but solitaire the stick with the single its cheaper.

Tim have you had any dealings with the Asus CUV4X-D I'm stuck with mine...

 

[e_storm]

thanks for all the good posts fellas.

For me it sounds like a 1 chip system is best. I don't do anything crazy, mainly gaming and internet stuff. I was just playing with the idea of a 2 chip system, I think I'll stick with what I know. Thanks again to everyone.

E

 

[lightning]

Wow, i have a question over here, did any one of your ever hear about putting 2 different stepping cpu into Abit VP6 mobo? such ask putting one CC0 and CB0 cpu together! any idea?

 

[Renegade87]

Intel is somewhat vague on mixing different stepping cpu's in a dualie system. They say it is supported, but untested.

 

[Shadow ÒÓ]

Definitely going with Tim on the unstable part of SMP. I see no difference in dual or single.

As far as a user machine tho.....buy a single. For one you'll be able to sink the price of 2 processors in one huge one........and the cost of the board is a big savings as well that can be put into memory or hd's or something.

my Single 933 smokes my roomies dual 733. However like said above.....when he's running VB and Photoshop, I can't do the same tasks at near the speed.

I'm a gamer.......I'd never consider a dual board for games. The roomie's sys is much slower than mine when we're playing UT and we're both running 2k server.

 

[Tim-]

You can't use a cb0 and a cc0 together on a VP6 without hardware modifications to the motherboard. It sums the VID pins together from this combination, and sets the Vcore to 1.3V. This can be gotten around, but it's better and easier to get 2 of the same stepping.