How do CPU Speeds work?

brycematheson712

brycematheson712

New Member
This might be hard to explain and if you all don't get it, please just bare with me. This is something that I've always wondered but never really asked.

Okay, so as an example: So let's say that I've got a 32-bit single core CPU clocked in at 3.2 Ghz. But then I go notice a 64-bit Dual Core CPU that's clocked in running at 2.6 Ghz. How does that work? Shouldn't the Dual Core be clocked higher than the Single 32-bit core? This is the only thing I can think of:

So if the Dual-Core is clocked at 2.6 Ghz, since it's dual, you would double that speed, correct? So now, that's 2.6 X 2.6 = 5.2 Ghz. Now, since it is 64-bit verses 32-bit you would also double that because it's twice the bandwidth of the 32-bit correct? So now we're up to 10.4 Ghz. So a 2.6 Ghz 64-bit Dual Core is essentially 10.4 Ghz when compared to a 32-bit single cored CPU clocked at 3.2 Ghz?

Does that all make sense? Maybe I'm just confusing myself. Can somebody explain it to me? Thanks!
 
In a sense, you're sort of correct, but mostly no. A 2.6ghz dual core processor doesn't mean each core runs at 2.6ghz, that is a common misconception. Also, just because the CPU can recieve data to process faster, doesn't mean that it can process said data faster, so no, you also wouldn't be able to double it for 32- and 64-bit CPU's. However, you are correct that a 2.6ghz dual core CPU would be faster than a 3.2ghz single core CPU...I'm not quite sure why, but I think it has to do with the fact that in each CPU cycle, the two core can process more data...read here for some more info, or just wait for someone who is more familiar with the subject to respond :rolleyes: : http://en.wikipedia.org/wiki/Multi-core_(computing)
 
I'm ressurecting this thread in hopes that someone can try to explain this to me again. I'm always seeing dual core and quad core processors with "1.8Ghz" and "2.6Ghz", etc. I'm just not sure how all of it works and compares because I've built a single core 3.2 Ghz processor computer before. Certainly, 3.2 is more than a dual-core 1.8 right? Lol. (I know I'm wrong, I'm just using that as an example.)

Help please? Thanks!
 
Remember how AMD was top dog for so long even though all their CPU's were clocked a lot lower than Intels? Just think of one core in the new dual core and quad core CPU's being much more efficient then the higher clocked single core CPU's. These Core 2's aren't just lower clocked Pentium 4's, their a whole new design.
 
Thanks for the reply, and I'm flattered, but I still am confused.

It's not like people can just 'choose' how fast there processors are running...without lieing. I thought that is how you compare the two speeds? So...for example...how could a 1.7GHz AMD be the same as a 2.0Ghz Intel? Is that what you're saying?
 
brycematheson712 said:
Thanks for the reply, and I'm flattered, but I still am confused.

It's not like people can just 'choose' how fast there processors are running...without lieing. I thought that is how you compare the two speeds? So...for example...how could a 1.7GHz AMD be the same as a 2.0Ghz Intel? Is that what you're saying?
Click to expand...

A 1.7ghz AMD athlon 64 is faster than a 2.0ghz intel P4 because the Athlon 64 has longer pipelines, thus being overall more efficient per mhz. (don't quote me on that :))
 
what he means is that AMD cpu's can process more PER CLOCK CYCLE than intel's Pentium series. that makes up for thier lower clock speeds.
 
How about this:
CPU's have something called "Pipelines". The shorter they are, the less speed you need to get data to go through them. And yes, BOTH cores run at that speed, not a combined speed. That would be redundant to have as a combined speed.
 
Okay, so as an example: So let's say that I've got a 32-bit single core CPU clocked in at 3.2 Ghz. But then I go notice a 64-bit Dual Core CPU that's clocked in running at 2.6 Ghz. How does that work? Shouldn't the Dual Core be clocked higher than the Single 32-bit core? This is the only thing I can think of:
Click to expand...
The 'bits' of a CPU have no effect on how fast it is. A 64bit CPU isn't faster than a 32bit CPU just because it is 64bit. The design of the CPU is what makes it faster. A 3.2GHz Athlon 64 (single core) processes 1 task faster than a 2.6GHz Athlon 64 X2 (dual core). Slower clock dual cores are only faster than faster clocked single core CPUs when there is more than 1 thing to be done.

So if the Dual-Core is clocked at 2.6 Ghz, since it's dual, you would double that speed, correct? So now, that's 2.6 X 2.6 = 5.2 Ghz. Now, since it is 64-bit verses 32-bit you would also double that because it's twice the bandwidth of the 32-bit correct? So now we're up to 10.4 Ghz. So a 2.6 Ghz 64-bit Dual Core is essentially 10.4 Ghz when compared to a 32-bit single cored CPU clocked at 3.2 Ghz?
Click to expand...
Dual core 2.6GHz is not the same as a single core @ 5.2GHz. All dual core means is you can do 2 things at the same time. 64bit CPUs (of the same core version) are no different than a 32bit CPU. With a Pentium 4 530 & 531, the only difference is the 531 is 64bit. This means it can process 64bit integers and address 64bits of memory (side effect of 64bit integers), nothing more.
 
brycematheson712 said:
So if the Dual-Core is clocked at 2.6 Ghz, since it's dual, you would double that speed, correct?
Click to expand...

Only if the software is written for dual core will it take advantage of both cores. If it's not a multithreaded software application then it would only run on one core, therefor 2.6GHz. This is a quote taken from the Wikipedia article posted above:

"In addition to operating system (OS) support, adjustments to existing software are required to maximize utilization of the computing resources provided by multi-core processors. Also, the ability of multi-core processors to increase application performance depends on the use of multiple threads within applications. For example, most current (2006) video games will run faster on a 3 GHz single-core processor than on a 2GHz dual-core processor (of the same core architecture), despite the dual-core theoretically having more processing power, because they are incapable of efficiently using more than one core at a time [1] [2]."

Dual cores make better use of their power but since most of the software is not written for dual core (yet) their primary purpose is multi-tasking. Because almost all of the Video games I play are older games I use an AMD and Intel single cores in my gaming rigs and a Core 2 Duo in my work machine. Pretty soon all of the new games will be multithreaded for dual core and be DirectX10 so I'll be building a dual core/DX10 rig for gaming at some point.
 
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Cromewell said:
The 'bits' of a CPU have no effect on how fast it is. A 64bit CPU isn't faster than a 32bit CPU just because it is 64bit. The design of the CPU is what makes it faster. A 3.2GHz Athlon 64 (single core) processes 1 task faster than a 2.6GHz Athlon 64 X2 (dual core). Slower clock dual cores are only faster than faster clocked single core CPUs when there is more than 1 thing to be done.

Dual core 2.6GHz is not the same as a single core @ 5.2GHz. All dual core means is you can do 2 things at the same time. 64bit CPUs (of the same core version) are no different than a 32bit CPU. With a Pentium 4 530 & 531, the only difference is the 531 is 64bit. This means it can process 64bit integers and address 64bits of memory (side effect of 64bit integers), nothing more.
Click to expand...

so wht ur saying is that if im running ONE program with a say 2.6 GHz dual core vs ONE program with a 3.2 GHz single core....the single core program would work better...but if i ran TWO programs on a 2.6 GHz dual vs TWO programs 3.2 single that the dual core is faster at handling both programs?
 
So does Windows XP and Vista have support for Dual Cores now? I know that they 'support' it, but do they actually know how to spread the stress of the system equally over the two CPUs?

You keep saying that Dual Core is only for multi-tasking (at this point) but that must mean that Windows XP and Vista has the support for it so that there major programs can run smoothly and multi-task correctly.

And what about Quad-Cores? It's basically the same idea as the Dual-Cores correct? Just as soon as they're able to support more than one core, those will be better correct?

Also, how long do you think until the 64-bit architecture will be readily usable and offer more functionallity over the 32-bit?
 
XP and Vista support dual-cores, but Vista is suppose to "manage" dual cores better, by more efficiently spreading out the load.

XP actually does a decent job at it, but splitting the load of all the current processes running so that both cores perform as close to 50/50 as possible.
 
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