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What does the GHz of Macbook Pro Processors really mean?

G

greelsvish

macrumors newbie
Original poster
Dec 9, 2011
1
0
I was just browsing the Apple website, as they have recently update the specs of their Macbook Pro's. I've been teaching myself a lot of Computer hardware specs recently and I'm just getting to know what they all mean (I want to build my own computer some day).

Anyway, here's the line-up:

13-inch: 2.4 GHz
2.4GHz dual-core
Intel Core i5
4GB 1333MHz
500GB 5400-rpm
Intel HD Graphics 3000
Built-in battery (7 hours)
$1399

13-inch: 2.8 GHz
2.8GHz dual-core
Intel Core i7
4GB 1333MHz
750GB 5400-rpm
Intel HD Graphics 3000
Built-in battery (7 hours)
$1698

15-inch: 2.2 GHz
2.2GHz quad-core
Intel Core i7
4GB 1333MHz
500GB 5400-rpm
Intel HD Graphics 3000
AMD Radeon HD 6750M with 512MB GDDR5
Built-in battery (7 hours)
$2099

15-inch: 2.4 GHz
2.4GHz quad-core
Intel Core i7
4GB 1333MHz
750GB 5400-rpm
Intel HD Graphics 3000
AMD Radeon HD 6770M with 1GB GDDR5
Built-in battery (7 hours)
$2499

17-inch: 2.4 GHz
2.4GHz quad-core
Intel Core i7
4GB 1333MHz
750GB 5400-rpm
Intel HD Graphics 3000
AMD Radeon HD 6770M with 1GB GDDR5
Built-in battery (7 hours)
$2899

From what I thought I knew, the 2.8GHz 13" would be the fastest computer. I thought that the more GHz a processor has, the faster the computer is. Am I right? Surely this isn't true because otherwise all the higher range Macbook Pro's would have equal if not better processors. Please explain what makes a processor worth more, and why these laptops are priced as they are.

Any help would be much appreciated.
 
depends what you are doing. For single core apps, the higher clockspeed on the same architecture is faster. If you have programs that utilize more cores, then more core machines are faster (quad vs dual)
 
Well to start off, there is 1000mhz = 1ghz

Then it comes to processors, the 2.2ghz QUAD core will be faster than the 2.8ghz DUAL core at more CPU power intensive apps, but you wouldn't find much of a difference doing web browsing or word documenting.

Having more processors give the Mac more space to spread the processes out between so having 4 processors instead of 2 for example, even if the (2) has a higher clock, the likely hood is that the (4) would be a lot faster. It's pretty hard to explain without going into more 'techy' language, I hope you know I'm coming from, once you get the hang of it though you'll easily be able to base you idea on what the quicker Mac would be by balancing clock speed and the number of processors.

EDIT : Basically, having more processors gives the Mac (Or PC to that matter) more of a work surface to spread all of the apps/games etc. out on, making it a lot smoother, and a lot faster.
 
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Goftrey said:
Well to start off, there is 1000mhz = 1ghz

Then it comes to processors, the 2.2ghz QUAD core will be faster than the 2.8ghz DUAL core at more CPU power intensive apps, but you wouldn't find much of a difference doing web browsing or word documenting.

Having more processors give the Mac more space to spread the processes out between so having 4 processors instead of 2 for example, even if the (2) has a higher clock, the likely hood is that the (4) would be a lot faster. It's pretty hard to explain without going into more 'techy' language, I hope you know I'm coming from, once you get the hang of it though you'll easily be able to base you idea on what the quicker Mac would be by balancing clock speed and the number of processors.
Click to expand...

Ugh. Not quite. How it really works is as follows:
A Dual-Core CPU in effect has 2 "pipes" where the computer can do things. The clock speed is the rate each of the pipes operates at. Most programs used to only use 1 pipe at a time, so the benefits of multiple pipes didn't occur unless you we're doing lots of things at once (as more pipes means your Mac could do lots of things at once). These days a lot of programs are able to use 2 or 4 pipes simultaneously to get stuff done faster. So a Quad-Core at a slightly lower clock speed is much better for running modern applications as it lets you use 4 pipes at a time (even Mac OS X is optimised to use more than a single pipe at a time, so even the Finder is faster), instead of just the 2 in the Dual Core system. Hence a 2.2Ghz Quad Core is faster than a 2.8Ghz Dual Core for most things these days.
 
chrismacguy said:
Ugh. Not quite. How it really works is as follows:
A Dual-Core CPU in effect has 2 "pipes" where the computer can do things. The clock speed is the rate each of the pipes operates at. Most programs used to only use 1 pipe at a time, so the benefits of multiple pipes didn't occur unless you we're doing lots of things at once (as more pipes means your Mac could do lots of things at once). These days a lot of programs are able to use 2 or 4 pipes simultaneously to get stuff done faster. So a Quad-Core at a slightly lower clock speed is much better for running modern applications as it lets you use 4 pipes at a time (even Mac OS X is optimised to use more than a single pipe at a time, so even the Finder is faster), instead of just the 2 in the Dual Core system. Hence a 2.2Ghz Quad Core is faster than a 2.8Ghz Dual Core for most things these days.
Click to expand...

Isn't that what I basically said too? Without the pipes bit? :p
 
Given the use of turboboost by Intel, clock rates aren't even really fixed numbers anymore. The cpus are described by their base clock rates.
 
Goftrey said:
Isn't that what I basically said too? Without the pipes bit? :p
Click to expand...

Kind've, but you were a bit vague. The pipes analogy is very close to the truth (CPU Pipeline), and a bit less wishy washy than calling it space, given the Mac doesn't actually "spread" stuff out per-se, it just executes 4 things at once. Spreading doesn't really describe parallelisation.

And to zen: Nope, but I figured its relevant given we get asked this about Dual/Quad PowerMacs regularly.
 
For the OP, in case you're computer shopping, my suggestion would be for maximum speed, go for any of the quad core machines from 2011. I've seen a few in the Apple store in the $1300-1500 range, especially early 2011 machines which are still Sandy Bridge versions.
 
It is true, more Ghz more speed, but not necessarily more power, heres why

it doesnt tell you how many cores it has
it doesnt tell you about other features such as Turbo Boost(variable speed CPU)
which roughly translates to...the processor will increase its speed
to cope with more processes. This in reverse means that the CPU by
default is choosing a LOW speed until it cant cope too well so it then
Boosts its speed higher to cope better.

You can usually FORCE BOOSTED state from within the BIOS.

finally then a slight warning.

the current design philosophy is, we have reached our maximum speeds
so how can we improve our CPU's, well lets add extra Cores and lets make
our chipsets SAVE BATTERY which will EXTEND BATTERY life.

so they are making PC's more powerful not really using speed but
using DESIGNed in features of multiple cores.
____________________
dell laptops deals
 
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