Could someone please explain dual/quad core?

[SixTwoSix]

Hi there, new here and in the process of upgrading my system, but a little confused with dual core and so on.

My current system is a p4 2.4Ghz, so obviously it's about 4 years old, i haven't really checked up on any computer stuff since I bought it 4 years back. Now, i'm not a tech noob, i understand quite a bit, it's just that i've neglected to follow cpu development over the last 4 years or so.

Correct me if i'm wrong, but i'm guessing dual core means there are 2 cpu's working in conjunction with one another, so for example if you had a dual core 2.4Ghz, do you combine these and essentially have a 4.8ghz processor or doesn't it work like this. I've googled lots of articles, but can't seem to figure it out.

Last time I looked there were single core 3.2ghz chips and I just assumed this number would keep going up as it's done since my highschool days of 386's and so on.

Also I notice quad core, does this mean 4 cpu's, and if so, if you have a quad core 3ghz, does this mean a 12ghz system?

I know these are quite trivial questions as i'm guessing most of you know this stuff off by heart, but please be patient with me, thanks!

 

[topshot]

They are not seperate chips, they are built into one.

and no you dont add them together. a Quad core cpu clocked at 3Ghz is still 3Ghz but in applications that support multiple cores it means the work load can be split between the multiple cores

 

[SixTwoSix]

So you could in effect have 3 design programs open, be using a quad core and each core would deal with a different program?

 

[Dangerman3]

oh and btw if you ever go on e**y and you see someone selling a cpu and it say's look woow at quad core Q6600 9.6GHZ its a load of rubbish they have the whole concept of quad core wrong. people seem to think you add them up. thats totally wrong, same with dual core chips.

I have a p4 2.8 CPU you know when you open one thing and you go to open another and its a little slow opening (you know what i mean) well this is where quad/dual come into a world of their own. Each core in the cpu is split between an application.

Oh and if your thinking of buying a new cpu

QUAD CORE IS THE FUTURE

 

[Columbo]

So you could in effect have 3 design programs open, be using a quad core and each core would deal with a different program?

Only if all of those programs are 'Multi Core enabled'.

Because the technology is still relatively in its infancy a lot of software out there is only geared up for the standard single core.

We're now seeing the first batch of games coming with Multi core support. I have purchased a copy of Sony Vegas (proffessional video editing software) that supports up 8 cores and its runs like a dream.

 

[SixTwoSix]

Okey doke...thanks guys, think i've got my head around it now.

So then, if you were using programs that just supported single core, would you get the same performance on a single core 2.4ghz as a dual/quad core 2.4ghz, from what i've read it's pointless having the extra cores if the software doesn't support it?

 

[NeverWinter]

Prety much but multi tasking will be far better, and remember that you can set a programs affinity to specific cores.

 

[SixTwoSix]

So even if the program only supports single core, you can still assign a few different programs to different cores if you have to use them at the same time?

 

[Legoman]

So even if the program only supports single core, you can still assign a few different programs to different cores if you have to use them at the same time?

The O.S. (Windows) will distribute and balance the processes (programs) across the cores.

You can set a certain process affinity to a specific core.

This is useful for something like BOINC. You can assign affinity for that process to a specific core and it will run on that core at 100% utilization. All the remaining processes will run on the other core(s).

 

[Legoman]

Only if all of those programs are 'Multi Core enabled'.

Because the technology is still relatively in its infancy a lot of software out there is only geared up for the standard single core.

We're now seeing the first batch of games coming with Multi core support. I have purchased a copy of Sony Vegas (proffessional video editing software) that supports up 8 cores and its runs like a dream.

Surely the O.S. balances the processes (programs) across the cores. They don't have to be 'Multi Core enabled'

If you mean multi-thread enabled then the threads of a specific process (program) can be distributed across the cores taking advantage of the extra processing power and allowing that program to run much faster.

 

[Marse]

The O.S. (Windows) will distribute and balance the processes (programs) across the cores.

You can set a certain process affinity to a specific core.

With applications which only use one core do you have to allocate an affinity for each or will each application automatically be allocated a 'free' core, if avaialable.

 

[Dureth]

With applications which only use one core do you have to allocate an affinity for each or will each application automatically be allocated a 'free' core, if avaialable.

The OS will assign them to the core with the least load at any one time. All modern OS have very good schedulers (the aprt of the OS that assigns cores) and you can't beat them by assigning affinity yoursself except in extreme cases normally brought on by bugs.

 

[Legoman]

With applications which only use one core do you have to allocate an affinity for each or will each application automatically be allocated a 'free' core, if avaialable.

The O.S. will balance them across the available cores in real-time.

You only need to set affinity in specific circumstances, e.g. if you want a specific program or process to stay on one core while everything else runs on the other(s).

 

[Marse]

Thanks guys - well explained and understood.