How-To: Decode Apple’s Tech Specs pages before buying a new Mac (Part 1)

Buying a Mac is designed to be easy. Apple has a handful of different models, each generally available in good, better, and best configurations. You’re supposed to start with the specific Mac model that fits your needs, pick a configuration that has the price and features you want, and walk away happy with your purchase. (Better yet, do your research online and save money after ordering from Amazon, or use the product guides off to the bottom right of this page.)

One thing Apple tends to downplay are tech specs — important numbers and acronyms that nonetheless confuse many people. Look carefully on Apple’s web site and you’ll find that there’s a Tech Specs page for every Mac Apple sells; they’re the keys to making an informed Mac purchase that will be right for your current and future needs. My latest How-To is here to walk you through each of Apple’s specs with clear explanations, so you can understand what you’re about to buy. This Part 1 discusses the “big 5” Mac specs you need to know about, and Part 2 tackles the rest…

Display

Most Macs come with built-in screens, which Apple calls “Displays.” There are three key things you should understand about them, and several others that aren’t as important, but get mentioned in Apple’s marketing materials.

(1) Size. Mac laptop screens range from 11.6″ (MacBook Airs only) to 12″ (MacBook only) to 13.3″ (MacBook Airs and Pros) and 15.4″ (MacBook Pros only). Larger screens generally consume more power and require larger batteries. iMac desktop screens are either 21.5″ or 27″. (Mac minis and Mac Pros do not include screens, which you have to supply yourself.)

(2) Resolution. This is the number of tiny dots — pixels — that are used in the display. They’re always presented as a larger number (width) multiplied by a smaller number (height), and range from “1366 by 768″ (11.6” MacBook Air) to “5120 by 2880” (Retina 27″ iMac). To put this in context, a typical high-definition television has a 1920 by 1080 resolution.

(3) Retina or Not. This spec is critical, because it effectively tells you how detailed the screen will look given its size. If a Mac’s display has over 215 pixels per inch (ppi), too small to be seen by the human eye at normal viewing distances, Apple will call it a “Retina display” and typically provide the pixel density. For reference, the 15″ MacBook Pro is 220ppi, the 12″ MacBook is 226ppi, and the 13″ MacBook Pro is 227ppi. Apple notably doesn’t list this for the 27″ Retina iMac (217ppi), because people will erroneously conclude that the number’s too low. It’s not, because you sit further away from a big 27″ iMac screen than a small laptop screen.

(4) Supported (scaled) resolutions. The highest resolution a Mac display supports will be called “native;” that’s the raw resolution of the display. Apple also lists “scaled” resolutions, which means the Mac can draw an image with fewer pixels, then make it big enough to fit the display. This helps users who want larger text and icons on screen to easily make everything bigger.

(5) Aspect Ratio. Apple occasionally notes the dimensions of its laptop screens in a width to height ratio. The MacBook and MacBook Air are listed as 16:10, a little taller when contrasted with the 16:9 screens found in all HDTVs. This isn’t generally an important spec.

(6) LED-backlit / IPS Technology. Apple mentions both of these things even though almost all of their Mac screens have them. LED backlighting just refers to the way the screen is illuminated with power-efficient LED lights, and IPS (in-plane switching) indicates wide (but unspecified) screen viewing angles. IPS is notably left off of both MacBook Airs, which instead use an older screen technology called TN or Twisted Nematic, with weaker color accuracy at off-center viewing angles.

Processor

Processors (historically known as CPUs or central processing units) are one of Apple’s common differentiators between a model’s several configurations and price points.

(1) Processor Type. Apple now uses four key types of processors in Macs: the low-powered Intel Core M (12″ MacBook only), the mid-range and very similar Intel Core i5 and Intel Core i7 (found in almost all other Macs), and the workstation-class Intel Xeon E5 (Mac Pro only). The key thing to understand is that the Core i5 delivers the best balance of performance and power consumption for most people, while the Core M is low-powered and lower in performance, and the Xeon E5 uses a lot of power for higher performance. The Core i7 is a step between the Core i5 and Xeon E5, designed for “power users” who don’t want to spend extra money on the Mac Pro.

(2) Number of Cores. Almost all of Apple’s machines are either “dual-core” or “quad-core,” which means they have two or four identical processing units that can work together as needed, typically using more energy when the additional cores are active. On laptops, this can impact battery life; on desktops, there’s no compromise. The Mac Pro also comes in 6/8/12-core versions. Dual-core Macs have enough performance for most people.

(3) Clock Speed. Each processing core processes tasks at a certain speed, ranging from 1.1GHz (12″ MacBook) to 4.0GHz (the top-of-line 27″ Retina iMac). While a Mac at any of these speeds will be fine for web browsing, word processing, and playing videos, higher speeds (and more cores) give you a rough sense of how quickly a given Mac can complete complex tasks such as video rendering or photo editing. Faster Macs also tend to be much better for hard-core gaming.

(3.5) Cores Versus Clock Speed. Following initial publication of this article, a reader wrote to ask me,

“I’m comparing the top of the line iMac 4-core Intel Core i7 with 4GHz speed, with the 6-core Xeon E3 Mac Pro with 3.5G speed. I have light video, photo and audio editing, and the normal browsing/email, etc. Will the 6 cores letting more threads run at 3.5G do me better than 4 faster cores?”

My response, edited slightly:

“Think of cores versus clock speed as equivalent to a 6-person family with 6 decent cars or 4 excellent cars. Most of the time, it’s unlikely that all 6 cars will be in use simultaneously, so the family would get greater enjoyment when using fewer (but nicer) cars. But in the rare situation where 6 cars would be beneficial at once, the family will have to juggle things a little. Assume further that most families have 2 cars, but some families do indeed need 4 (or more), and few have 6 (or more).

This is imperfectly analogous to a 4-core iMac versus a 6-core Mac Pro. Most people use 2-core machines without complaints. Power users choosing between 4 or 6 cores will occasionally benefit from having extra cores to handle ultra-heavy-duty tasks, but under most circumstances will be better served with fewer, faster cores (especially at a lower price). The $1,200+ you save buying an iMac instead of the Mac Pro will pay for a SSD for your iMac, which will kick the performance up even further, and still cost less, even in a configuration with extra RAM for the iMac.

(4) Turbo Boost. Intel’s chips are able to hit peak “Turbo Boost” speeds higher than their normal clock speeds when necessary, typically consuming extra power to do so. The 12″ MacBook can more than double its speed from 1.1GHz to 2.4GHz, and the 4.0GHz Retina 27″ iMac jumps modestly to 4.4GHz.

(5) L3 Cache. Also known as “Level 3 cache,” this is extra working memory devoted solely to the processor cores. It ranges from as little as 3MB in entry-level Macs to as much as 30MB in some Mac Pros. L3 cache impacts the speed of each Mac configuration in ways that are rarely quantified.

Memory

Memory (often known as RAM) is another key differentiator between various Mac configurations. The most critical factor is the amount of RAM (read my Guide to Boosting Mac RAM here), but there are other differences worth knowing as well.

(1) Amount. This number is important because it defines how many small and large apps a Mac can have running at the same time without speed penalties. It ranges from a low of 4GB (gigabytes) in entry-level models to a base of 16GB in the 15″ MacBook Pro and Mac Pro. If you’re buying a Mac in 2015 and don’t have 8GB or more, you’re setting yourself up for disappointment.

(2) Configuration / Number of Slots / User-Accessible. Some Macs have two or four slots for RAM. If so, Apple may indicate that the 8GB of RAM is two 4GB sticks in two RAM slots, or that a Mac Pro has 64GB spread across four RAM slots. The number of slots and the user’s ability to access them are only important if you plan to expand the Mac’s RAM in the future. If you don’t, or the RAM is not specifically listed as user-accessible, make sure your Mac has at least 8GB when you buy it.

(3) Speed. RAM speed isn’t typically something users need to be concerned about. It ranges from 1600MHz in the Mac mini, 12″ MacBook, and 15″ MacBook Pro to 1866MHz in the 13″ MacBook Pro and Mac Pro.

(4) Type. Users don’t need to be concerned about this at all; all Macs use variations on “DDR3” (double data rate type three) RAM. The Mac mini, 12″ MacBook, MacBook Air, 13″ MacBook Pro and low-end 21.5″ iMac use LPDDR3 (“low power” DDR3), the 15″ MacBook Pro uses DDR3L (“low voltage), most iMacs use regular DDR3, and the Mac Pro uses DDR3 ECC (error-correcting code) for higher reliability.

Storage

If I was personally picking the two most important specs when buying a Mac, Storage would be neck-and-neck with Processor. As I’ve mentioned in my hard drive-to-SSD replacement guides for iMac, MacBooks, and other Macs, old-fashioned hard drives are on the way out, and affordable new solid state drives (SSDs) can more radically increase the overall performance of Macs than small processor differences.

(1) Type. Apple currently uses three different types of storage devices in Macs. Traditional hard drives (sometimes listed as Serial ATA or SATA drives) are the oldest and slowest. SSDs are the fastest and typically the most expensive. Fusion Drives mix traditional hard drive and SSD technologies to reach high capacities at midrange price points.

(2) Capacity. Storage capacities start at 500GB for traditional hard drives (Mac mini) to 128GB for SSDs (MacBook Air). Apple’s Fusion Drives max out at 3TB (terabytes), versus 1TB for SSDs. If you’re shopping today, 256GB should be the barest minimum for an SSD, 1TB for a traditional or Fusion solution.

(3) Speed. Apple currently only sells traditional hard drives at 5400RPM speeds; faster 7200RPM models are offered in external enclosures. SSDs have no speed specifications, but Apple has recently badged newer SSDs as “PCIe-based flash storage” to indicate that they’re faster than earlier (unmarked, but actually SATA-3) SSD models. It does not specify the actual speeds of Fusion Drives, but they’re faster than traditional drives and slower than SSDs.

Graphics and Video Support

I’m including graphics (also known as GPU, graphics chip, or graphics card) in the “big 5” because video rendering capabilities are an important factor for certain users: computer gamers and hard-core video editors. But at this point, Intel’s most basic graphics chipsets can easily power Macs for virtually everything else, and do a good enough job for games and video editing that typical customers won’t complain. Except for the Mac Pro, you typically cannot replace the graphics chips in Macs after purchasing them.

(1) Intel, AMD, or NVIDIA Graphics. Intel is Apple’s primary supplier of Mac graphics chips, starting with Intel HD Graphics 4000 (the old Macbook Pro), 5000 (Mac mini, low-end 21.5″ iMac), 5300 (12″ MacBook), and 6000 (MacBook Air). The Intel Iris Graphics 6100 is found in the 13″ MacBook Pro, while the Iris Pro is included in better 21.5″ iMacs and as the main graphics chip in the 15″ MacBook Pro. AMD’s Radeon R9 M290X is found in the 27″ Retina iMac, with regular 27″ iMacs sporting NVIDIA GeForce GT 755M or GTX 775M processors, and Mac Pros including dual AMD FirePro D300/D500 video cards.

(2) Second Graphics Card: High-end 15″ MacBook Pros can switch as needed between the energy-efficient Iris Pro and a more powerful NVIDIA GeForce GT 750M.

(3) Graphics RAM: Apple includes between 1GB to 4GB of dedicated graphics RAM on most of its machines, which will matter mostly to serious gamers.

(4) Graphics RAM Speed: The graphics cards on Macs universally use fast GDDR5 RAM.

(5) External Display Support: Every Mac supports at least one external display, even if one is already built into the computer. Standard iMacs and MacBook Airs support one 2560 by 1600 display;  the 15″ MacBook Pro supports two external displays with the same resolution. Similarly, the new 12″ MacBook supports one display at up to Ultra HD 4K (3840×2160) resolution, while the 13″ MacBook Pro supports two at that resolution, and the Mac Pro can power three.

(6) HDMI Video Output: All Macs currently support full-resolution, full-speed output to HDTVs using standard HDMI cables: 1080p at 60Hz (frames per second). Some, including Pro models, are also capable of outputting 3840 by 2160 Ultra HD 4K at 30Hz, and 4096 by 2160 at 24Hz — not quite as fast as regular HD, but with 4 times the pixels.

(7) Thunderbolt Digital Output: If listed, this indicates that the Mac can connect to an external computer monitor using a Mini DisplayPort-style connector, as contrasted with the HDMI connectors found on all HDTVs.

In Part 2 of this How-To, I’ll walk through all the other key components worth knowing about before making a Mac purchase. Save cash on your Mac purchase by ordering from Amazon, which offers aggressive discounts on prior-generation machines, as well as savings on many current-generation Macs, or use the 9to5Mac product guides to the right.