[edit] Dual Processor systems- how much faster are they in my situation?

[absolutiza]

Can anyone tell me just how fast (relatively) are dual-processor systems? Say I stick 2 1Ghz CPUs in a dual-processor mobo. How much faster will that be than if it just had one processor? I heard that it wouldn't be faster at all unless you were running a program that was programed for dual-processor architecture.

 

[Athlon4all]

They are only 2 situations where Dual processors increase performance. One is when Multitasking. It does help when multitasking. 2 like you said when the application is SMP optimized. It really isn't worth it IMO for the power user.

 

[Modus]

It depends.

First, you have to be running an SMP-enabled OS like Windows NT4 or 2000. Then you will get some benefit from multi-threaded applications (typically professional graphics and software development). The SMP-aware OS will also delegate tasks to both CPU's when there is more than one application running. And some applications, particularly 3D rendering and graphics, are fully SMP-aware in themselves.

None of these situations will display the full 100% performance increase after adding the second CPU for real-world applications. The benefit depends on how optimized the software is and how conducive it is to CPU performance; for instance, an application limited by memory bandwidth or hard drive performance is not going to improve much from a second CPU. But an app that's computationally-intensive will see a definite speed boost. This boost varies widely from one app to the other, but for heavily optimized apps, it tends to hover between 30% and 60%.

At the moment, there are no value-oriented SMP platforms: dual P3's are hilariously more expensive than a single, fast Athlon that usually outperforms them, and dual Athlon's require a very expensive motherboard and power supply. Wait a couple months, and we will see cheap dual Socket-A boards that use regular ATX power supplies. Then SMP might be worth it.

Modus

Modus

 

[Zach]

Yeah, in ideal conditions you're luck to go 50% faster.. so a coupld 800's are lucky to be as fast as a 1.2. And guess which system wouold be cheaper?

I'd only consider duallies for servers, or just to burn cash and have fun (which I could imagine doing myself).

 

[Soccerman]

But an app that's computationally-intensive will see a definite speed boost.

such as Seti@Home or RC5, hehe..

seriously though, in situations where your CPU might normally become bogged down (say you're burning a CD and for some reason it would normally mean not doing anything else on your computer), if you were running an OS that was SMP aware, you may end up not really feeling any effect in performance. Of course, situations like this should not occur if the computer is configured properly, and has good enough hardware to offload the CPU.

 

[dullard]

<< They are only 2 situations where Dual processors increase performance. One is when Multitasking. It does help when multitasking. 2 like you said when the application is SMP optimized. It really isn't worth it IMO for the power user. >>



Ahh you forgot situation number 3. Suppose you have a bloated operating system that is capable of using more than one processor. In the single processor machine, you have to share the CPU time betweeen your programs and the operating system. In a dual processor machine, the operating system may be handled by one CPU and a CPU intensive program will be handled by the other processor. The benefit depends on how bloated the OS is. For example, WinNT takes about 2% of my resources, Win2k takes roughly 4%. I haven't yet tried WinXP but lets assume it takes 5% of the CPU time to do all of its bloated stuff. Thus I will see a 2-5% improvement on programs that aren't even SMP capable. Since it takes a 10% improvement to be really noticible, this is a minor improvement. But if you want all the juice you can get, 2% may be what you are looking for.

The benefit in programs capable of using both processors varies drastically. Suppose I try a small task which a single processor is quite capable of performing - I get at most a 10% improvement when using both processors to do that same task. When I try a task that requires one processor several hours/days to finish - I get a 80%-110% improvement by using both of my processors. And of course, in between I often see 30%-50% speed improvement, but then I usually never run medium sided problems. There is no single answer we can give you, unless we knew exactly which programs you will use and how heavily you will tax them.

By the way, I use two different dual processor machines every day (dual 450 MHz and dual 1.7 GHz). For my work, the extra cost saves me lots of time and money. It probably isn't worth the extra cost for the vast majority of users.

Edit: corrected spelling.

 

[joohang]

<< It really isn't worth it IMO for the power user. >>


IMO, it is worth every penny for power users.

absolutiza: Unless you run VERY CPU-intensive and/or multi-threaded apps, I would say that the benefits of SMP are mostly the "smoothness" of operations. Everything simply runs much smoother, especially when you are heavily multitasking with a CPU-intensive app, whether it's multithreaded or not.

So in terms of raw performance, most people likely won't benefit from it. For benefits of smoother multitasking, that's a matter of personal taste.

 

[absolutiza]

what exactly do you mean by cpu-intensive programs? examples?

i'm just a regular user really. sometimes i'll be running several apps at once like burning a CD and playing music or a video game or have several explorer windows open. i also use x-win a lot with SSH telnet.

So, given these programs that I run, will I see any real improvement in performance? I'm getting that it's not even worth it

 

[duke]

I can say that my dual 464Mhz Celerons are just as fast, if not faster, in Photoshop than my 1Ghz Pentium III at work.

 

[bozo1]

I notice practically NO difference in everyday stuff with my duals. When I'm in Photoshop or Premiere or crunching SETI I see about a 75-80% speed improvement.

Very few people actually do any sort of real 'multitasking' beyond like burning a CD or playing MP3's while surfing. Most people are just task switching.

 

[CocaCola5]

I think even average users would like to run their dvd, cdr, music encoding, etc, without having to worry about the quality(or crash) of the output if they perform two or more of these tasks at the same time. Tasks that rely on a "continuous stream", is very difficult to multitask with only one cpu. This is the everyday mundane benefit of smp, you don't need high end apps to see the return.

 

[dullard]

<< what exactly do you mean by cpu-intensive programs? examples?

i'm just a regular user really. sometimes i'll be running several apps at once like burning a CD and playing music or a video game or have several explorer windows open. i also use x-win a lot with SSH telnet.

So, given these programs that I run, will I see any real improvement in performance? I'm getting that it's not even worth it >>



Ok steps you need to take:
1) You must boot WinNT, Win2k, business WinXP, or some unix verson to get ANY effect from a dual processor machine.
2) Load task manager or similar program - in WinNT or in Win2k right click on the taskbar.
3) Switch to the 'Performance' tab in task manager.
4) Run your programs as usual.
5) Watch the CPU usage. If it hits 100% and stays there for significant periods of time, you either need a faster processor or possibly a dual processor machine.

For the programs you listed, you will not see more than a few percentage increase in performance (for a few hundred dollars investment). I think you would be much better off with a faster CPU than with two CPUs. An example of a CPU intensive program is this.

 

[Sugadaddy]

<< At the moment, there are no value-oriented SMP platforms: dual P3's are hilariously more expensive than a single, fast Athlon that usually outperforms them, and dual Athlon's require a very expensive motherboard and power supply. >>



Tyan Tiger K7 ?? Relatively cheap for a dual mobo (230$), works with regular ATX power supplies. (I checked and my Enermax 350W is enough according to Tyan's web site)

 

[Strafe]

So to answer your question Abso, you'd see a minimal difference. In other words, it not worth it when just doing standard task switching stuff.

 

[absolutiza]

Thanks for your input.