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
Comments Locked

233 Comments

View All Comments

  • darwinosx - Monday, June 24, 2013 - link

    Another peson who didn't read the article and knows nothing about Macs.
  • watersb - Monday, June 24, 2013 - link

    Excellent review!

    If only it were available with RAM...
  • darwinosx - Monday, June 24, 2013 - link

    If only you took tow seconds to find out you can order it with 8 GB of ram.
  • appliance5000 - Friday, December 20, 2013 - link

    It's available with 8gb ram - but here's the rub: If you have the 512gb ssd coupled with the fact that it's mounted on the pcie bus, your page ins and outs are about as fast as memory - or seemingly so. It's a very fast machine - I've tested it stitching multi gb panos and editing multi gb layered files in CS6 and it just rips.
  • FrozenDarkness - Monday, June 24, 2013 - link

    I think people get retina confused with higher resolution computers. Couple things, your windows computer? DPI up scaling sucks too much to truly run retina. Know that retina on a 13 MBP actually runs at a resolution of 1280x800 to be truly "retina" or else you're just up-scaling then down-scaling and burning your graphics card in the process. So in a sense, it's not truly higher resolution in terms of workspace, just in terms of beauty to behold. This also means a MBA retina would have to be a different, higher resolution panel, than the one used in the 13" MBP and at that point, what is the point of the MBP? I think you're more likely to see the MBP become more lik the MBA in size than vice versa.

    Also, panel lottery sucks, let's not act like apple is the only manufacturer who has a panel lottery or that samsung are only in "review" units.
  • A5 - Monday, June 24, 2013 - link

    Windows 8.1 is supposed to fix the DPI scaling in Windows. Win8 is already significantly better than 7.

    Beyond that, sharper pixels even without an increased workspace is still a good thing. I think the rMBPs have a mode that does both, anyway.
  • JarJarThomas - Tuesday, June 25, 2013 - link

    Windows 8.1 can't fix the dpi scaling in windows cause the problem is that most desktop applications can't scale well.

    Fixing dpi scaling with win8 would be similar to the solution apple does for non retine enabled grafics, internally upscale it.

    But that would not work with the way the windows grafic stack works and the applications are dependent on this.

    So scaling will ONLY be better for modern ui apps, not for desktop apps.
    And therefore it will suck
  • akdj - Wednesday, June 26, 2013 - link

    'Desktop applications can't scale well' because and ONLY because of the underlying OS. It's up to the operating systems architecture to provide third party scaling options/abilities. As we've seen with the rMBP....in less than a year, literally hundreds of apps....from small developers ala Pixelmator to the monsters...AKA, Adobe....have updated their 'code' for HiDPI displays. As has Apple with their software....and Windows with their native apps. Look at the Surface Pro for instance. Anything other than native Windows programming is a PITA. Windows 8.1 absolutely can help...regardless of how the graphic stack is set up....it's that low level coding that Windows needs to get creative with. Especially with dozens of OEMs, screen sizes and ratios....it will absolutely fall into Windows hands to provide decent scaling options and APIs for developers. High Rez monitors aren't going anywhere. 4k was all the rage at CES this year....and $7,000 Sony 4k TVs are already at Best Buys.
    OSx meanwhile has done an excellent job with pixel doubling trickery for text....while allowing developers the ability to natively use every pixel available 'in app' when drawing, editing video or stills....et al.
    That said, and as a rMBP and 11" Air owner, I can honestly say the Air's resolution doesn't bug me in the least. It's a 2011 core i7 and I use it daily....right along side my 15" rMBP...which is the best computer I've ever purchased. Almost a full year with it and it still brings a smile to my face. I started my computer life @ 14 with an Apple IIe in '85. I remember being jealous when my buddy got the 'color' screen for his IIc...while I continued to slave away on a green monochrome screen. Lol....I suppose its where we come from, our ages....and therefore, appreciation for higher resolution vs decent resolution (11" Air) more than adequate and a helluva lot better than other choices on the market. Dunno
  • Bkord123 - Tuesday, June 25, 2013 - link

    I do not claim to know a ton about computers, and I'll be honest, half of this review looks like it's written in Latin to me. However, regarding the comment that Windows 8 is better than 7, didn't I read several headlines that Windows 8 is more or less responsible for a massive decline in PC sales?
  • TheinsanegamerN - Sunday, June 30, 2013 - link

    the main reason pc sales are declining is a mix of a poor economy and computers lasting longer. machines reached the point of being fast enough for consumers five or six years ago. most consumers dont run out to get the newest thing in laptops, they wait until their current one breaks, which is more pronounced when jobs are not certain and raises are nonexistent. they were declining before windows 8 made it to market, though windows 8 isnt helping at all.

Log in

Don't have an account? Sign up now