A Case Study in Why CPU Performance is Important -- Anandtech

bplewis24

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Jul 15, 2011
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Since most reviews for any new iPad (let alone any new Apple product) tend to ONLY focus on the areas where Apple blows the competition away--in this case, GPU performance--and never where it struggles, I thought this would be worth it's own thread:

iPhoto: A Case Study in Why More CPU Performance is Important
In our section on iPhoto we mentioned just how frustratingly slow the app can be when attempting to use many of its editing tools. In profiling the app it becomes abundantly clear why it's slow. Despite iPhoto being largely visual, it's extremely CPU bound. For whatever reason, simply having iPhoto open is enough to eat up an entire CPU core. Perhaps this is why Apple forbids the application from running on a first generation iPad, with only one CPU core.

Use virtually any of the editing tools and you'll see 50 - 95% utilization of the remaining, unused core. The screenshot below is what I saw during use of the saturation brush:

iphoto.jpg


The problem is not only are the two A9s not fast enough to deal with the needs of iPhoto, but anything that needs to get done in the background while you're using iPhoto is going to suffer as well. This is most obvious when you look at how long it takes for UI elements within iPhoto to respond when you're editing them. It's very rare that we see an application behave like this on iOS, even Infinity Blade only uses a single core most of the time, but iPhoto is a real exception.

I have to admit, I owe NVIDIA an apology here. While I still believe that quad-cores are mostly unnecessary for current smartphone/tablet workloads, iPhoto is a very tangible example of where Apple could have benefitted from having four CPU cores on A5X. Even an increase in CPU frequency would have helped. In this case, Apple had much bigger fish to fry: figuring out how to drive all 3.1M pixels on the Retina Display.

Apple clearly has been focusing on GPU performance with the last few iterations of it's mobile product line and the reason is clear: they are heavily interested in mobile gaming and the revenue potential it has. But Android has held the edge in CPU performance OS-wide and across a wide range of mobile products for a few years now.

This italicized quotable is also a good illustration of the "fragmentation" that many iPhophants refuse to admit exists within the Apple ecosystem and always hypocritically bash Android for.

AnandTech - The Apple iPad Review (2012)