A multi-core processor?

[Tuomas]

Hi there again.

I was consulted by my friend last night. He's thinking of getting a new computer and is between a laptop and the normal desktop ones, and wants me to help him because I usually do just that. He'd be taking the old one to their band's training facilities for recordig purposes.

Last night he asked me if I knew why the other computer he had been looking at had a 1,7 GHz processor and the other had a 1,7 GHz dual-core processor. He couldn't tell me the exact names, but they were both AMD. I told him, that as far as I know, a multi-core one is better, but he caught me by asking "how exactly are the better?"

It's actually a funny thing. I googled for hours about mutli-cores and normal single core processors and all I could find were discussions at forums like

"what different about this new technology?"
"It's a lot better, that's all you need to know"

"Does a dual core mean, that I get 3,2GHz one to work at 3,2 + 3,2 = 6,4?"
"It doesn't multiply the power, so that's not worth talking about"

But no-one would give an answer, just noobs specualting and people tellig them what it isn't doing. So I basically know what a mutli-core doesn't do, say, raid a Pendoline-train while it's moving or blow the whole universe up, but I really don't know what's the use.

Some claimed it'd help with games that could handle it, keeping the background processes ran through the other core and the game through the other, but still no-one mentionend what the benefit of that was.

I'm used to getting good answers from here, so please, if someone knew why they were better, if that really is the truth, and why my friend should pay more for one of those? Yeah, he uses the computer to play games that need a bit more power, I guess.

[Oliwerko]

Interesting question, Tuomas.

I own a quad-core proccessor and I can tell you it's fast. I have had a dillema between a dual core 3Ghz and quad core 2,4 Ghz that costed the same. (Both Intels) I have read about some tests. And conclusion? Newer software is written to get the most out of the multicore proccessors. No, it does not multiply the power, you do not get twice that much. I do not really know how exactly better it is, but IMHO if you have a program that can handle multi-core proccessors and a multi-core proccessor, you have a great advantage.

I never searched for exact benefits, however. I think "It's a lot better, that's all you need to know" is kind of sufficient for me, I don't need to know the proccessor on its basis. I just think it's all about proccessor-software symbiosis when the program gets much more power from a multi-core than a from single one.

I have heard that some of the newer games are designed only for quad-cores, that means the game itself is written to use 4 cores. You can imagine what will happen if it don't.

If it's a gaming computer, I say the more cores the better, and definitely a desktop.

[SSH]

Start up the Windows Task Manager. On my PC just now I have 109 processes, 6 or 7 of which are actively consuming CPU resource. Multitasking time slices your CPU between the active processes and so only one thing happens at once meaning all these processes are competing for your single core. Having more cores lets more things happen at once, when they need to.

[Haddas]

Exactly. The more cores you have the better they share the load. I guess you can compare it to a highway with one lane and four lanes. the speedlimit remains the same but the flow of traffic is smoother.

[Makeout Patrol]

It really does make a noticable difference, too - for instance, back when I used a single-core processor, if I wanted to, say, burn a DVD or export a movie, I had to leave the computer alone until it finished, because that took up pretty much the whole capacity of the processor. Now if I want to do either of those, I can surf or use photoshop or whatever while it's working.

[Oliwerko]

Yeah, try quad on compressing and saving a wmv to DivX avi.
Back on my single core it was like one second = one frame. Now? One second = 20/30 frames. Also some advanced audio stuff runs a lot better.

[LGM]

SSH and Haddas hit it right on. Multi-Cores come from the same root as multi-tasking, meaning that your computer won't get bogged down with just one process. On single core, even at fast clock speeds (3.0+) if you were rendering video and such, every other process gets hammered down until you're done with. However, on my intel dual-core I can burn a DVD and watch a full-res movie without any lagging or glitches. It's more a matter of convenience, to me anyway, than any speed boost. I do alot of stuff at the same time. So, ideally, the more cores the better. However, most software has to be written to utilize multiple cores. So you'll see most of the benefits with newer software more than you would, say, with Solitaire.

If it's a matter of dual and quad, right now, I'd say go with the dual. It will be faster (clock speed wise) than the quad, and would get most anything done quickly and efficiently. Unless your friend does a lot of heavy audio/video production work, I'd say go with the dual. The Quad's are (relatively speaking) in an early stage, and won't really provide a huge benefit to anyone who is not aware of them.

[Shane 'ProgZmax' Stevens]

The real practical benefit of multiple cores right now seems to lie in video editing, 3d rendering and music mastering software, programs which all take a notoriously large chunk of your cpu's attention.  As a simple comparison, I use Renoise 2.08 for making music, and on my 1.8 ghz single core using about 6 KORG instruments from the Legacy vst at once would literally cripple my cpu (the usage meter would regularly go over 80% and sometimes to 100).  When I got a 2.2 ghz dual core I found I could use the same 6 instruments and barely get to 30-35% cpu usage, so there's definitely a pay off for people who use applications.  This doesn't apply so much to modern games, though I'm sure eventually they'll get around to needing 8 cores or some ridiculous value!

[InCreator]

2 x 2,18 GHz Intel DualCore here.

I don't really see much improvement in music or video editing. Windows XP Home seems to burn first core, and if its usage gets near 100%, utilizes next core. Second cpu has ALWAYS less load, even when machine is really busy.


Windows performing a complex and delicate task named "Open task manager"

As you can see from performance graph, First core took about 80% of the load at the second I pressed Ctrl-alt-del.

3D rendering is better, that I must admit. I can do really cpu-killing stuff, stuff that isn't meant to be done really before next 20 years, and it's... well, doable. Like GI and caustics. It's still strange to see how those, not-so-new and not-so-complex things still cripple fairly powerful and modern machine down to a crawl.

I wouldn't say dualcore is a very big power gain, for example, going from 1GB of RAM to 2GB is waaaay more noticeable, especially in massive video and sound works, but I wouldn't go back to singlecore machine either.

This is not mathematics, I'm speaking of personal feel here, game performance, so on.

I have no clue what quadcores do, but I guess there's even less difference.

If I had to upgrade something, I would go for hard disk with higher rpm. I saw one, and nothing is comparable to how simple extra 3000 rpm could multiply speed of opening and loading everything.

[Oliwerko]

.....not to mention the difference between 16 and 32MB cache.

[Tuomas]

Thanks guys, thanks a lot. This is the first place I got any advice on this so far, in any language I tried. I'm probably going to recommend my mate to get that dual-core, though it's only after a few weeks he'll have time to go look for one as he's doing some hard working hours at the moment.