The CPUs

Apple keeps things simple across the 2013 MacBook Air lineup by configuring both 11 and 13-inch models with the same base CPU: a Core i5-4250U.

To understand Apple’s CPU choice, you have to understand that Apple is primarily concerned about improving battery life this generation. The line between MacBook Air and MacBook Pro has to be well defined. The Air is about portability, while the Pro is about performance. When faced with a power/performance tradeoff, it’s clear on which side of the fence Apple will fall whenever the MacBook Air is concerned.

Apple 2013 MacBook Air CPU Comparison
  1.3GHz dual-core 1.7GHz dual-core
Standard On 11 & 13-inch MBA Optional on Both
Intel Model Core i5-4250U Core i7-4650U
Base Clock Speed 1.3GHz 1.7GHz
Max SC Turbo 2.6GHz 3.3GHz
Max DC Turbo 2.3GHz 2.9GHz
L3 Cache 3MB 4MB
TSX-NI No Yes
TXT No Yes
AES-NI Yes Yes
VT-x/VT-x EPT Yes Yes
VT-d Yes Yes
TDP 15W 15W
Processor Graphics Intel HD 5000 Intel HD 5000
GPU Clock (Base/Max) 200/1000MHz 200/1100MHz

The lower base clock alone shouldn’t mean much, but the max TDP of the CPUs in the new MacBook Air falls as well - from 17W down to 15W. The thermal limit is even more dramatic since with Haswell ULT, the 15W includes the CPU/GPU as well as the on-package PCH. In Ivy Bridge the PCH was off package and wasn’t included in the 17W TDP.

Max turbo clocks are identical between the Haswell ULT CPUs Apple picked this round and the Ivy Bridge models before, but with a lower TDP it’ll be harder to always sustain the same frequencies given the right workload.

Haswell does feature a not insignificant gain in IPC compared to Ivy Bridge, which should help offset the power constraints that could otherwise force a larger regression in performance.

Both 2013 MBAs ship with the same CPU by default, and both can be upgraded to the same higher end SKU: a Core i7-4650U. The 4650U retains the same 15W TDP as the i5-4250U, but it increases its base clock speed to 1.7GHz and max turbo to 3.3GHz. The L3 cache also grows from 3MB to 4MB. All in all, this should be a very healthy upgrade in performance. Intel likely maintains the same TDP by binning for power; the i7-4650U is probably capable of running at higher frequencies without any appreciable increase in voltage. The max GPU clock also goes up by 10%.

Haswell ULT, Courtesy iFixit

What's arguably coolest about the i7-4650U is it enables Haswell's Transactional Synchronization Extensions (TSX-NI), a feature which is unfortunately disabled on the i5-4250U. I don't suspect this will matter much for most MBA users, but anyone looking to play around with Haswell's TSX instructions will want to opt for the higher end SKU. The upgrade costs $150 regardless of base model. Intel charges $454 for the i7-4650U and $342 for the i5-4250U, a difference of $112; Apple is adding another $38 onto the 1KU pricing, which isn't unreasonable.

Many have asked me what the impact of the i7 will be on battery life. I'm hoping to get my hands on an i7 based machine when I return from the UK in a week, but for those of you making immediate decisions I'll offer the following. Sustained operation at higher frequencies will likely draw more power, and negatively impact battery life. Light to medium workloads will enjoy a mix of race to sleep benefits as well as higher power consumption under load. Idle power should be roughly similar between the parts however. For most workloads I'd expect a modest impact to battery life, but it won't be enough to regress to 2012 levels of battery life. All of this is said without knowing key details like operating voltage for most 4650Us. I plan on addressing that shortly.

 

Introduction CPU Performance
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  • darwinosx - Monday, June 24, 2013 - link

    They are not biased and you don't understand the meaning of the word. Reply
  • MonkeyPaw - Monday, June 24, 2013 - link

    Just a thought, but how about stating your concerns via constructive criticism or in the form of a question. Crying bias while continuing to visit (and therefore, support) any website just doesn't make much sense since you will be dismissed as a troll by the very people you are hoping to influence. Reply
  • CalaverasGrande - Monday, June 24, 2013 - link

    Frankly I think users that expect to play heavy 3D games on a MacBook Air with chipset video bought the wrong computer. They should have spent a few hundred more for a 15" MBP with discrete graphics. Or if they really care about games they should hop the fence and go get an Asus or some other Windows gaming notebook.
    Intel's HD4000 graphics are better than previous Intel video attempts, but still pretty weak compared to other vid chips. It's also using system ram, not dedicated ram.
    As stated, this is the mobility platform, not the performance platform.
    Reply
  • CalaverasGrande - Monday, June 24, 2013 - link

    oops, HD5000. Reply
  • darwinosx - Monday, June 24, 2013 - link

    Nobody does. But the HD 5000 is quite capable for some games. Reply
  • hyrule4927 - Monday, June 24, 2013 - link

    The lack of thermal data in these Mac reviews is rather frustrating. If this data is included in all other PC reviews in Anandtech, why is it completely ignored when reviewing Apple products? They certainly aren't immune to heat/throttling problems. Reply
  • darwinosx - Monday, June 24, 2013 - link

    You didn't read the article you are commenting on. Reply
  • hyrule4927 - Monday, June 24, 2013 - link

    If you would like to tell me where specific CPU temperature data is given, be my guest. All I see is an anecdote about fan noise and speculation about throttling in several tests. Reply
  • darwinosx - Monday, June 24, 2013 - link

    Prove that Samsung makes a better screen than LG. I bet you can't tell the difference. Reply
  • spronkey - Monday, June 24, 2013 - link

    Samsung LCDs might have slightly better early quality control. LG Display have been a bit notorious for early run issues with their panels lately. But I agree - taking these away, LG has more cred as a panel maker than Samsung does. Reply

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