Different base clock speed, same turbo boost?

[cairene2011]

Hello there!

I currently use a MacBook Air 11" from 2011 that's run by a 1.7 i7 GHz processor featuring a 3.3 GHz turbo boost.
Now I've spoiled my eyes with the Retina screen of my iPad resulting in the upgrade of my "blurry" MBA to a MacBook Pro Retina 13".

The turbo boost for both my current MBA as well as the MBPr of my choice (2.6 i5) is 3.3 GHz. I don't know how exactly this boost works, but I assume that under heavy usage the processor will jump into "boost mode" until the base clock speed cuts it again. I hence imagine that I will not see any speed improvements with the MBPr, "boost mode" will simply be used less often (and save battery life this way?).

While my current MBA has to work with 4GB memory, the 8GB of the MBPr will be a welcome speed increase in multitasking (especially video rendering in the background). But will there be any noticeable power improvement processor-wise (eg faster rendering) if the maximum speed is the same 3.3 GHz?

Of course, Haswell is a superior processor to whatever was used in 2011 (sandy bridge?), but how exactly does this play out in real life? Does it at all?

 

[thundersteele]

1. A 2013 (Haswell CPU) is faster than a 2011 (Sandy Bridge?) CPU at the same clock speed.

2. Turbo boost can only kick in until the thermal head room is used up, i.e. until the CPU is too hot. Then the rMBP will clock back to 2.6 GHz while the Air will go down to 1.7 GHz. So for any kind of tasks that require computing power for more than a few seconds, the rMBP will be faster.

You can compare performance on e.g. Geekbench. The rMBP seems to be about 40% faster in single core use and about 50% in multi core benchmarks, compared to your 2011 MBA. It is not a crazy jump, but together with more RAM and faster graphics and data transfer rates, it should make for a nice speed bump.


PS: Concerning 2, it seems the Air has a lot of room there. If you compare 2013 rMBPs and MBAs, their performance is very similar, the rMBP seems to have a lead only in multi-core benchmarks.

 

[cairene2011]

1. A 2013 (Haswell CPU) is faster than a 2011 (Sandy Bridge?) CPU at the same clock speed .....

Thank you, thundersteele! That was a really helpful and comprehensible answer, I greatly appreciate it.