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.
[image source]
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.
Using the Intel power gadget (above) shows your CPU running at low speed.
In normal case that would be fine if there is no load.
I have MBA with 1.8 GHz Intel Core i5 and runs at 0.85 at normal use, how ever it does spikes to 1.8 + under load.
Since the computer processing speed depends on more than one factor (CPU +SSD read/Write+RAM)...
I would say you (your mac) is a candidate for the Apple Hardware test.
UPDATE:
If you have faulty battery (as reported by your hardware test based) then your Mac will automatically limit the CPU speed to about 1/2 (as designed by Apple.)
So fix the battery and you good to go.
Best Answer
3,1GHz is a single core maximum. Like when running prime95 on one core.
http://www.intel.com/content/www/us/en/architecture-and-technology/turbo-boost/turbo-boost-technology.html Intel has a sneaky way of suggesting that it will work on all cores under some conditions but that's just advertising unfortunately.