Dual Core, double core?

[Ambient]

When there is a dual core processor and it shows the processor power i.e. 2.5 Ghz, is that 2.5 x2= 5ghz or 1.25 x 1.25 = 2.5ghz?

[MunkeyQ]

That's two cores, each one running at 2.5ghz. However, this does not mean it equal to a 5ghz processor. You can't add the speed of the cores up to make a total speed.

[BaconPie]

Am I right in saying that it's not 5GHz but two 2.5GHz running at the same time?

Like a two lane road with car's traveling at 25mph instead of a one lane road with one car traveling at 50mph. Or is that the worst analogy ever?

Also, which would be faster, or is it ENTIRELY dependent on the way it's coded?

[Agent 008]

The thing most people don't realize about multicore processors, is that it is very likely they would be better off with a faster uni-core processor, than with several slower cores.

The reason for that, is that most people only run one main processor-intensive task at a time. (E.g. a game, or just processing something)

And, unless this processor-intensive task is implemented using concurrency, only one core will be used to run it.

So, on a uni-core processor, it will take 99% of the processor time, giving 1% to background tasks.

On a multi-core processor, it will take 100% of one core's time.

Considering multi-core processors often have slower cores than a uni-core processor would have, it may actually result in decreased performance.

So in short, it can only get close to doubling the speed of your application, if this application is implemented in a way that separates the task into two concurrent processes with roughly equal loads.

[LiquidIce]

However, you can assign some uh archiving to be done on one core while putting IMs, Photoshop, AIMP, Firefox on the other core voila, everything should work like magic.

Now just figure out why sometimes Vista won't let me set core affinity.

[Agent 008]

However, you can assign some uh archiving to be done on one core while putting IMs, Photoshop, AIMP, Firefox on the other core voila, everything should work like magic.

Now just figure out why sometimes Vista won't let me set core affinity.

Yes - but most of the time for most people, they only use one processor-intensive process.

Either way, having anything more than a dual-core is a waste of money at the moment, imho.

[Cir]

Given what Agent 008 said, would it then be feasible to have a dual-core, non-symmetrical processor, with say, a 1.2ghz core for background/low intensity stuff, and a higher power 3.2+ core specifically to handle that one intensive application properly? Is that possible, or am I just being foolish?

[Agent 008]

Given what Agent 008 said, would it then be feasible to have a dual-core, non-symmetrical processor, with say, a 1.2ghz core for background/low intensity stuff, and a higher power 3.2+ core specifically to handle that one intensive application properly? Is that possible, or am I just being foolish?

I haven't heard of them doing those.

What do you intend to use it for, mostly? That would help us recommend you what to get.

[Cir]

I haven't heard of them doing those.

What do you intend to use it for, mostly? That would help us recommend you what to get.

I wasn't intending on getting one, I was just wondering if it would be more efficient than a single or dual core. I don't even know if they exist.

[Agent 008]

I wasn't intending on getting one, I was just wondering if it would be more efficient than a single or dual core. I don't even know if they exist.

Then it depends on what you're getting it for.

Let's say you had one 3.2Ghz core. Let's also say that background apps take 5% of processor time. As a result, your primary application gets 3.04 Ghz.

Now, let's say you have two cores at 2.5Ghz. Your main app uses 100% of the first core, and your background stuff uses 5% of the other one. You lose out on more than .5Ghz with this setup. And getting a second slower core? Makes the .16Ghz quite expensive.

Then again - if you are performing something that is efficiently split between processors, you will get somewhere around 20-40% benefit in speed (keeping in mind the overhead from message exchange, synchronisation etc.) Or if you load your processors with many small processor-hungry tasks, you may get twice as much done.

It all depends on the tasks.

For an average home user? Wouldn't notice any benefits, if at all.

[Dfg]

I did a small test and boy i was surprise.

On a Intel 2.66 Ghz (Dell Gx260) system a DVR software would take around 98% Usage.
On an Intel 2.4 Ghz (Dell Gx260) it will take around again 95% Usage.
On an Intel Dual Core 2.8Ghz it will take around 9~12% Usage.


Conclusion, forget what everyone says Dual Core>Single Core. (When it comes to CPU intensive tasks)

[shuaid]

wtf? multicore is awesome its great for gamers. many new games utilize multiple cores. I beg to differ agent.