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Why are Intel processors getting slower in MBP?

patrickkidd

patrickkidd

macrumors newbie
Original poster
Mar 11, 2010
24
1
Sausalito, CA
I'm sure someone can answer this right away, but why are the processor frequencies getting slower in the processors that Intel is putting in the MacBook Pros? Right now the fastest CPU you can get is a 2.4GHz. Why don't they have > 3GHz? Is there some other factor that keeps these machines fast?
 
patrickkidd said:
I'm sure someone can answer this right away, but why are the processor frequencies getting slower in the processors that Intel is putting in the MacBook Pros? Right now the fastest CPU you can get is a 2.4GHz. Why don't they have > 3GHz? Is there some other factor that keeps these machines fast?
Click to expand...
Many are quad-core vs dual-core. 2.4GHz Quad > 2.4GHz Dual
 
Exactly as GG said, and you can get a 2.8 Quad core. With the hyper threading and turbo (which pushes it well past 3.4) the limitations become getting the clock specs in the smaller die spaces. As each generation gets smaller and more efficient, the speed increases as well as the need for the extra speed decreases due to the smaller dies spacing on the chip.
 
Not exactly true. The last refresh sent the 13" base MBP from having a 2.3ghz processor to a 2.4ghz processor.

Sandy bridge allows for hyperthreading and turbo boost which has thus far allowed for cores to clock at lower frequencies, while still trouncing the performance of yesterday's processors.
 
Moreover, the cache is larger in the newer lower GHz processors, the number of cores is up, and they offer new functionality like Hyperthreading and Turbo Boost which can take processors over 3GHz for single threaded processes. The raw computational ability of these chips is greater than the older higher GHz models with less cores, etc.
 
patrickkidd said:
Right now the fastest CPU you can get is a 2.4GHz. Why don't they have > 3GHz? Is there some other factor that keeps these machines fast?
Click to expand...

Because clock speeds are but one factor that makes a CPU peform faster. other factors including cores, multithreading and what not are better alternatives to making a CPU faster.

The higher the clock rate, the more power it consumes and hotter it gets. While 3GHz or above is ok for a desktop with lots of fans, evacuating that heat in a small enclosed laptop is much harder.
 
patrickkidd said:
Where can you get a 2.8GHz chip? I see a max of 2.5 on 17" 15".
Click to expand...

You can't. Only a 2.8 GHz dual core in the 13".

Remember that CPU clock speeds should only be compared amongst otherwise identical, or almost identical CPU architectures. For example, a dual core 3.2 GHz Pentium 4 is going to be trounced by a dual 2 GHz i5, let alone a quad 2.4 GHz i7.

Also, the modern mobile quads can overclock by around 50% when running single threaded applications. That's how you get >3 GHz.
 
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2.8 GHz dual core i7 in the 13". You are right about the 2.5 for the quad, but you only asked about raw clock speeds and didn't specify what was the most powerful processor available, as programs written specifically for dual cores, such as some games, have been shown to perform better on optimized dual cores even when compared to running on a competitive quad core, just based on architecture and the code handling. Power handling and speed performance are in totally different categories.
 
They are not getting slower!

The clock speed is not the only measure of "speed", actually it's a very bad one. A faster CPU should be able to perform more operations per second - this is one deciding factor in which CPU to use. For mobile machines, an even more important measure is efficiency, i.e. the amount of battery power each operation needs.

Quite a few years ago Intel noticed that just increasing the clock speed is not a very efficient way of improving the performance of a CPU for consumer PCs. Since then they have focussed on improved architectures and on using more cores per CPU.

Very simply speaking, a quad core CPU with 2.5 GHz is about as powerful as a dual core with 5 Ghz. However a 5 GHz dual core CPU would need as much cooling and as much power as a car engine, while a 2.5 GHz quad core can be kept at a reasonable temperature with the tiny fans and heatsink in the MBP.
 
Clock speeds don't tell you much about performance. If you're comparing two similar CPUs (eg. quad vs quad) within the same generation, they give you a decent indication of relative performance but they don't work as an estimate outside of those limitations. Clock speed tells you how many clock cycles the CPU goes through per second but it doesn't tell you what they do per clock cycle.

Intel got out of the "ghz wars" quite some time ago. They seem to be focusing on instructions per cycle nowadays so you won't see clock speeds increasing significantly even though performance is increasing.
 
If you're concerned about clock speeds, ask Intel. The 2.5 Quad that Apple uses is the highest model 45W sandy bridge processor that Intel offers and the second highest mobile sandy bridge processor that Intel makes. The 2.8 Dual in the 13" Pro is the highest dual core sandy bridge mobile CPU that intel makes.

btw, even the 1.6GHZ i5 in the MBA will run circles around the older 3.8GHZ Pentium 4 Extreme Editions from years ago...
 
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