How much faster are the custom configured Core i7-powered "Mid-2011" MacBook Air models than the stock Core i5-powered models? Is the extra performance worth the extra cost?

For each of the stock "Mid-2011" MacBook Air models -- the MacBook Air "Core i5" 1.6 11-Inch (Mid-2011) and "Core i5" 1.7 13-Inch (Mid-2011) -- Apple offers a 1.8 GHz Core i7 (I7-2677M) processor as a "configure-to-order" upgrade. For convenience, EveryMac.com also crosslists these CTO configurations as their own models.

Photo Credit: Apple, Inc. (Left - 11" MacBook Air, Right - 13" MacBook Air)

Custom configuring the MC969LL/A configuration of the 11-Inch model -- which has 4 GB of RAM and 128 GB of flash storage by default -- with the faster Core i7 processor costs an extra US$150. Custom configuring the MC966LL/A configuration of the 13-Inch model -- which has 4 GB of RAM and 256 GB of flash storage by default -- with the faster processor only costs an extra US$100.

General Performance & Value Overview

In percentage terms, upgrading the processor costs an additional 12.5% and an additional 6.25%, respectively, for the 11-Inch and 13-Inch models.

For a solid general overview of the performance differences between these custom configured models and the stock models, as well as other Macs, EveryMac.com's own Ultimate Mac Comparison makes it quick to compare side-by-side 32-bit and 64-bit Geekbench benchmark averages with all other G3 and later Macs for thousands of possible performance comparisons.

The Geekbench benchmark shows that when custom configured with the Core i7 processor, the 11-Inch and 13-Inch models are roughly 27% and 8.5% faster than their respective stock models.

Consequently, a quick calculation would conclude that the Core i7 upgrade is a good value for the 11-Inch model -- providing 27% more performance for 12.5% more money -- whereas the value of the upgrade for the 13-Inch model is more marginal.

Real-World Test Results

Geekbench always is useful for a convenient overview of overall performance, but real-world tests also can be helpful.

In independent "Lab Tests," MacWorld largely confirmed the Geekbench results:

[For the 11-Inch model], Cinebench CPU and file compression tests ran 21 percent faster, our iTunes encode went 19 percent faster, and our HandBrake test went 14 percent faster. . . [For the 13-Inch model], Compressing a 4GB folder was seven percent faster, the Cinebench CPU test ran five percent faster, and our HandBrake and iMovie encoding tests were three percent faster.

The always detailed AnandTech also provided a followup review for the 11-Inch model custom configured with the Core i7 processor and found "an average increase in performance of 22%." This also largely confirms the Geekbench results.

Performance & Value Summary

For those who have basic needs or who are on a tight budget, the standard Core i5 configurations of the "Mid-2011" MacBook Air should be sufficient (although a used MacBook Air would be less expensive still). What is a minor amount of money to one person may be substantial to another. Consequently, whether or not the extra performance of a "Mid-2011" MacBook Air model custom configured with a Core i7 processor is "worth it" likewise may be a decision based on personal finances.

Ultimately, however, the 11-Inch "Mid-2011" MacBook Air upgraded with a Core i7 processor is a good value and money well spent. Only those who really need the most power possible in a 13-Inch MacBook Air should consider the Core i7 processor upgrade as the performance-to-value ratio still is worthwhile, but less attractive.

Site sponsor PowerMax has new and used MacBook Air models available free of sales tax.

Also see: How fast are the "Mid-2011" MacBook Air models compared to one another and to earlier MacBook Air models? How fast are these models compared to the "Early 2011" MacBook Pro models?