cpumacbook promacos
The full spec for the 2017 12" MacBook is an i7 Kaby Lake cpu with 1.4 GHz base frequency and Turbo up to 3.6 GHz.
Various articles on the web state that the i7 used is specifically this model:
Intel i7-7Y75
Looking this up on Intel Ark shows the base frequency as 1.3 GHz.
Why is the stated base frequency on Apple's website higher than the one in Intel Ark? Does Apple use a factory overclock on the i7's in their MacBooks?
So, I ran some Cinebench R11.5 benchmarks to get more information about the single threaded performance of my i5-3427U1 (1.8-2.8 GHz) CPU:
1 thread → 1.10
I also contacted the author of the linked article by AnandTech - @anandshimpi2. Anand Lal Shimpi was so kind to send me a benchark chart which compared the single threaded performance of the 2011 13" Macbook Airs with the 2012 13" Macbook Airs using Cinebench R11.5.
Into this picture, I have added information about the maximum single threaded CPU clocks along with a comparison of the measured performance such as Anand Lal Shimpi has suggested.
In this info graphic I am comparing specifically:
- 2011 13" Macbook Air, i5-2557M 1.7GHz/2.4GHz/2.7GHz
- 2012 13" Macbook Air, i5-3427U 1.8GHz/2.6GHz/2.8GHz
As you can see, the single threaded clock of the 2012 model is 3.7% increased in turbo boost mode.
However, the benchmark score saw a 9.9% increase which is not simply due to the higher clock, but also due to the more efficient Ivy Bridge architecture which is about 5-15% faster3 than Sandy Bridge.
In sum, the benchmark scores are as expected whereas the Turbo Ratios log entries are not. Anand Lal Shimpi had "figured it was a bug, submitted it to Apple back in July"4.
So there are a bunch of comments about the merit of the question which it seems you e taken the time to look at and assess. I'll jump right in to starting the discussion on upgrading.
Firstly, to be clear you're looking at a new early 2015 13" MBP (I assume you're not interested in a 15", which can support quad core processors and add a whole new layer to the discussion).
Apple's tech specs can be hard to track down, but it looks to me like you got the same processors I did. The i7 supports a turbo up to 3.1 GHz and 4 MB of cache, with the i5s boasting 2.1 and 2.7 GHz processors and 3 MB of cache. You're right in that the i7 supports VT-d, but you'll need some fairly heavy duty software to take advantage of it. The answer about VT-d is that it really depends what sort of virtualization software you're using, my guess being that unless you want to use expensive commercial software, Oracle's VirtualBox will be the first to support that (though I have no reason to expect this, or know when).
This brings us to the next level: is the i7 worth it over the i5 (will there be notable performance gains)? For you (and others with this question), probably. The increased cache, better cache coherency, and outright speed increase will be what you notice. Being that all the processors for the 13" are dual core, I was unable to find evidence that there is any significant difference between hyper threading moving up and down Intel's CPU line (unlikely, they all use the same basic core).
Best Answer
The key phrase that you alluded to was
(emphasis mine).
From the Intel Ark spec sheet link you provided
(TDP is Thermal Design Power - or the wattage it dissipates with all cores running at normal operating frequency - the "baseline" if you will)
A little bit further in the Specs you will find the following values:
What this is telling us is that the CPU can be configured up or down by tweaking the speed and TDP values. It can go up to 1.6 GHz (1.4GHz is within this limit) or down to 600 MHz. More speed, more heat, more power consumption; less speed, less heat, less power consumption. It's up to the integrator to decide what makes most sense for them.
Apple made the decision to tweak it to 1.4 GHz.