Seems like GHZ was the way to do it up until 1.5 GHZ was commonplace. Is that still the case?
If so, why don’t manufacturers include the GHz rating on their product label along with “Pentassium Excitilator III Processor”?
If not, how does one select a quality CPU these days?
Are there any reasons I would want a 2.5 GHz processor when a 3.2 is available for essentially the same price?
You want to google the term “cpu benchmarks.” Comparing on mhz has always been a mistake, its just more obvious now.
I don’t have a good answer for you, but I’ll second you on the confusion bit. There are core-duo processors and dual-core processors. Seems to be a difference, but what is it? And which is better?
Allthough GHz is less of a factor these days, If you are comparing two processors that are the ‘same’ but have different Ghz values. The one with the higher value will be faster.
In other words an Intel core2 2.0ghz won’t be as fast as an intel core2 2.6ghz.
And one slightly limited way of comparing is number of cores.
I took the lazy option - I chose intel. I chose four cores instead of two. And I chose the highest Ghz they had. I prefer intel to AMD because when I had an AMD processor it tended to require more ‘work’ to make it work properly. And I was sceptical about the claims that a ‘slower’ AMD was as fast as a ‘faster’ intel.
Oh boy, this will get complicated.
For one, CPU architectures for general computers have pretty much all moved in the direction of multiple cores. You can think of each core as a separate CPU, only you get more than one core in a single package.
Multi core systems are interesting, because for technical reasons that I can’t explain in any detail, for general-purpose CPUs it’s much easier and cheaper to build a system that has 2 cores at any given speed than to build a single core that will run effectively at twice the speed.
On the other hand, to make effective use of multi core/multi cpu systems you need to either run multiple applications that take full use of a single core or you need applications that will use multiple cores at the same time. Some/many programs will do this already, but it’s not at all straightforward or useful for a lot of applications. This will get especially interesting when common computers will have 8 or more cores (this will be pretty soon).
Then there is the fact that Ghz speed hasn’t been a very good predictor of actual real-world efficiency for quite a while; all kinds of optimizations can be made to make heavily-used but slow constructs faster while keeping the Ghz speed constant or even running parts of the code in parallel on a single core. A couple of years back I bought a laptop with an intel pentium M (single core) which was noticably faster than the desktop machine I owned (also single core), which had a higher clock speed.
As a very general hint, for pure raw processing power, you’ll want a pretty recent CPU (because of those other optimizations) with as many cores times clock speed as you can get. If you just want a good deal on decent power, get a dual core CPU; they’re about at the right price/performance point, single core CPUs are on their way out, except on cheap/low-power architectures like netbooks and other portable items. And even if you’re not running apps that make use of multiple cores, you’re probably running more than 1 app at a time often enough that it will make a noticable difference.
Dual core is a generic term describing “two CPUs” in a single chip. core-duo is an intel name for a specific set of their chips that have 2 cores in them.
To confuse things further a ‘Core 2’ processor can have four cores in it.
Thanks.
By the by, how many cores are there in an Apple? 
8 physical cores in a Mac Pro with “Nehalem” processors. Intel’s HyperThreading makes them behave like 16 virtual cores.
I can explain this if anyone is interested.
However, more to the point, benchmarks are the only way to go. But they aren’t enough. Far more important is the applications you will be using. If you have lots of fairly simple parallel threads, lots of cores do very well. If you are doing heavy duty arithmetic processing, you want to pay attention to the floating point unit, since a slow one of these will be the bottleneck. If you are doing gaming the GPU may be more important.
If you are only doing randoms low intensity gaming, web surfing, and word processing, it doesn’t really make a difference, so long as you have enough power and memory to handle operating system bloat.
Woohoo! A favorite topic of mine!
As was said earlier, MHz and now GHz was never a really great way of comparing. If I said I had a 999 GHz processor, but all it could do was add, would that be useful? Probably not. And there were companies that made processors with artificially high speeds and few features because people thought they were better.
There are lots and lots of other factors that give you a net better or worse processor. Theoretically, a dual core processor (2 cores) should be twice as fast as single core, right? Wrong. Because it’s difficult for the software to split itself onto two processors, the gain is actually significantly less… many programs (though usually older ones) don’t see any benefit at all, and many of the ones that do see gains of only 20% or so. A processor with more cache will be able to do faster memory transfers in some cases, but that’s only useful to you when you need that feature. And so the story goes with any particular feature of a processor.
The upshot of all of this is like HorseloverFat said… “cpu benchmarks”. You need to choose what kind of applications to test (ie. if you want a gaming computer, you don’t want to look at scientific benchmarks and vice versa), and then look at benchmarks for that kind of application. If you’re into overclocking, you’ll also want to look at benchmarks of overclocked processors (again, clock speed increase isn’t everything).
By and large, what you’ll see is that Intel’s Core 2 line is the current king (though, again, it depends on your application). Before the Core 2s came out, AMD processors were generally better, though, and so anything that says “Pentium” is probably too old to consider anymore. The family of processor is probably most important. Within any given family of processors (ie. among a group of all Core 2 Duos but NOT among a group having both Core 2 Duos and Core Duos) a faster GHz rating is probably the most important thing left (cache size doesn’t usually matter all that much, for instance).
If all you want is to be able to watch movies and read email, do yourself a favor and go cheap. Those are very simple applications these days and don’t need much processing power.
Intel hasn’t shipped its 8-core CPUs yet.
Yeah. The Mac Pro is dual quad core.
Well, it’s version 2 of the Intel’s “Core” architecture. My laptop has a Core Duo processor in it, but not a Core 2 Duo. Now, it would be really confusing if Core 2 Duo processors were available in quad-core designs…
“Core 2” doesn’t refer to the number of cores on the CPU, it’s the name of the architecture, similar to how “pentium 3” was the name of an architecture. Core 2 duo refers to a dual-cored core 2, and core 2 quad refers to a 4 cored version.
This is out of date. Intel’s i7 architecture has been the performance leader for most of a year now.
In Many ways the I7 chips behave as 8.
Each of the four cores can process up to two threads simultaneously, so the processor appears to the OS as eight CPUs. This feature was present in the older NetBurst microarchitecture but was never introduced into Core since Core was a descendant of the Pentium III family.
I will submit that MHz was a good yardstick for performance…
…for 8086s through the first Pentium line…
It’s not. A 2.4 ghz i7 will have over an order of magnitude more processing power than a 3.2 ghz pentium 4.
That’s a bit mis-leading, hyperthreading doesn’t give nearly the same performance boost as adding another core.
Here’s a list of performance benchmarks for the current range of CPUs:
http://www.tomshardware.co.uk/charts/2009-desktop-cpu-charts/benchmarks,60.html
You’ll notice that the difference in performance varies greatly depending on the task.
The Intel Core 2 E5300 (dual core, 2.6 Ghz) and AMD Phenom II X2 Dual Core 550 (3.1 Ghz) offer good value for money.
Is this why when I look at my Core Temps, Core 1 is always hotter than Core 2?