Apple MacBook Pro 15-inch vs 13-inch: Is Core i5 Worth It?

By Ryan Whitwam

Apple just refreshed their laptop line today. But what's the difference between the new 13 and 15-inch notebooks?

Apple has finally announced updated versions of their popular MacBook Pro family of laptops. As expected, the updates include Intel's speedy mobile Core i5 and Core i7 CPUs. However, these new CPU options are only available for the 15 and 17-inch MacBook Pros (and surprisingly, the 15-inch is the only one with a Core i7 options). The 13-inch MacBook Pro is still stuck with a Core 2 Duo CPU (albiet with higher clock speeds), and an unchanged price. Apple seems to finally be differentiating their laptop line with this move. Most people aren't in the market for a 17-inch notebook, so it often comes down to the two smaller models. 
Previously, the 13" MacBook Pro was undeniably the more attractive option given that it shared the same internal specs as the 15 inch model. Now that the two models are more radically differentiated, there are some notable tradeoffs to consider if you're looking to save some cash. The highest specced 13-inch and lowest specced 15-inch are only only priced $300 apart, and we think they're the models that most people will decide between. We take a closer look at the details to see if the tradeoffs are worth the cost.  

CPU Performance

The highest spec 13-inch MacBok Pro now sports a 2.66GHz Intel Core 2 Duo CPU (Intel's Penryn-based P8800). This is slight bump from the 2.2GHz chip Core 2 Duo chip in yesterday's model. By comparison, the lowest specced 15-inch model comes with the much faster 2.4GHz Core i5 processor (the dual-core i5 520M). Here, advantage of the Nehalem CPU is significant. As the laptops have just been released, there are few real benchmarks of them, but we can gain some understanding from the performance of these chips in notebooks from other manufacturers.

In a variety of benchmarks, the Core i5 CPU appears to be 20-30% faster than the Core 2 chip from the 13-incher. It's no surprise the Core i5 outperforms the last generation Core 2 chips considering its new architecture, Hyper-threading, and TurboBoost technology. In case you don't remember Hyper-threading from the P4 days, it allows each core to run another virtual core, making multi-threaded apps faster. TurboBoost is a new technology from Nehalem that allows the CPU to automatically overclock itself when taxed, making single threaded applications faster.

RAM, Storage, and GPU

In the memory department, all MacBook Pro's are equipped with 4GB of RAM, so there's no difference here. The high-end 13-inch MacBook Pro comes with the same 320GB 5400RPM hard drive as the low end 15-inch does. So you're not gaining anything there either. But one big difference in the graphics department. The 13-inch model has a custom Nvidia 320M integrated GPU which is roughly half as fast as the Nvidia GeForce GT 330M found in the 15-inch model. That by itself is a nice performance increase, but Apple has another trick up its sleeve for the high-end GPU.

The 15 and 17-inch MacBook Pros now have an graphics switching system being called simply "automatic graphics switching". Many assumed this would be Nvidia Optimus technology, but Apple insists they're using their own tech here. Judging by what we know of Optimus, this system would only route power to the GPU when it was needed. When word processing or browsing the web, Intel integrated graphics will be used. If a graphics-intensive application starts up, the Nvidia GPU is activated and the display rendering would automatically and seamlessly switch to that. This has the potential to allow solid graphics performance while saving battery life. If you go for a 13-inch MacBook Pro, you don't get this feature.

LCD Display

Next, we come to the displays of these two models, which are obviously quite different. The 13-inch version has a 1280x800 native resolution, while the cheapest 15-inch model has a 1440x900 native resolution panel. For $200 more, the 15-inch has options for 1680x1050 displays and anti-glare screens. Either way, you'll get the unique unibody aluminum construction we're accustomed to on Apple's Pro laptops. Apple is also claiming the new notebooks will get up to 10 hours battery life -- even on the models with the discreet GPU thanks to the graphics switching technology. 

Size and Weight

 Finally, you have to consider the size and weight of the two models. With the increased power and screen space of the 15-inch version, you're also tacking on 1.1 pounds of extra weight. (Interestingly enough, that weight difference is close to the weight of an iPad). And though both models are equally thick (.95 inches), the extra screen size means the 15-inch model takes up 25.3 cubic inches of more space than the 13-inch model (most of this due to added width). This definitely affects how comfortable it is to bring these laptops on both short trips to the coffee shop and long trips across the country (and what laptop bag you will need). From personal use, we can testify that this size and weight difference does matter a lot when lugging around a notebook all day around a school campus or convention hall. It's the difference between a sore shoulder at the end of the day as opposed to a really sore shoulder.

What are the attributes of a high-end notebook that matter most to you?