How To Buy A Smartphone: What Do Hardware Specs Mean?

Smartphone manufacturers like to throw a lot of specifications at potential customers. But how many consumers know or care what they mean? Specs inform consumers but also have the potential to confuse. Here's what you need to know about smartphone hardware. (Part 4 of a 6-part series.)

Battery Life

Most phone manufacturers report battery capacity in a unit known as mAh. It stands for milliampere hours, a measure of how long the device will run before the battery needs to be recharged. The higher this number is, the better. It is a good basis for comparison when looking at multiple smartphones. Most manufacturers also list battery capacity in more consumer friendly terms like talk time or video playback time. For instance, Apple does not tell consumers how many mAh the iPhone 5 has, but it trumpets 10 hours of video playback. 

See also: How Much Should You Pay? 

Batteries continue to improve with each generation of smartphone. The recently announced Nokia Lumia 920 has a 2000mAh battery, as does the Droid Razr M. The Samsung Galaxy Note 2 will have a 3200mAh battery. However, this does not necessarily mean it lasts longer than that of the Lumia, since the Note’s screen is bigger and draws more power.

The best smartphones now will have upward of 2000mAh of battery life that translates into 10-plus hours of talk, video playback, or Web use, or four times that for audio playback. Motorola and Nokia are among the leaders in battery technology with Apple and Samsung not far behind.  

Number Of Cores

As many geeks will tell you, battery life means nothing if the device's compute (CPU) and graphics (GPU) processors do not manage performance efficiently. A single-core processor that runs at 1.2GHz (Gigahertz, a measure of how fast the device executes computations) is not going to have a lot of battery life. This is where we get into the concept of multiple cores. The functions of a smartphone on a dual-core processor can be split among the cores for more efficient performance. Not all smartphones are created equal though and core performance will vary depending on where the processor comes from and the smartphone manufacturer. 

Bottom line: Look for a high GHz number and at least two cores. It is a little bit more complicated than that, but essentially that is what performance in modern computing (smartphones, tablets or personal computers) is based on. Most top-of-the-line smartphones now run near 1.5GHz on two cores.

You may have heard about quad-core smartphones. The performance and power management of quad-core smartphones is better than dual-core, but you will not find them in the U.S., as most smartphone manufacturers release dual-core smartphones in the U.S. to better manage power on 4G LTE and 3G networks. 

The next evolution of CPUs in smartphones will be known as "plus one." Essentially, smartphones will have dual or quad-core processors plus one more processor to perform a specific function, such as graphics. 

See Also: Which Carrier Should You Choose?

Whereas CPUs manage how fast and efficient the functions of a smartphone operate, GPUs are designed to better handle graphics. For instance, the iPad 3 has an extremely sharp screen resolution and hence needs GPUs to render images. In this case, manufacturers can add more GPUs to a device to help it render better graphics but, unlike CPUs, the more GPU cores, the more drain on the battery. 

You may have heard of names like ARM or x86 when it comes to smartphone processors. Almost all smartphones and tablets right now are built on ARM because it is much more power-efficient than x86. Intel, the world’s largest chip maker, makes x86 and has not broken into the mobile market in any meaningful way. ARM processors come from companies like Samsung, Qualcomm, Nvidia or Texas Instruments. Each manufacturer has its own specialties, but the important thing to remember is the vast majority of smartphones are based on ARM.

Screen resolution

Screen resolution is one of the specifications that manufacturers, especially Apple, throw at consumers most commonly. It is measured in two ways: density of pixels per inch (ppi) and total pixel dimensions. To understand density, imagine a one-inch square box. Then place dots in that box. Those dots are pixels and the more of them in that box, the crisper and “richer” the picture will be. Right now, the resolution leader in smartphones is Apple. Keep in mind that higher resolution adversely affects battery life if the graphics processor is not up to snuff. 

Apple’s iPhone 5 has a ppi of 326 (same as the iPhone 4S). Its overall size, as measured by pixels along the length and width of the screen, is 1136x640. The Samsung Galaxy S III, the iPhone’s biggest competitor, has 306ppi and a 1280x720 screen. Technically, the Galaxy has more pixels, but the screen is larger, 4.7-inches to the iPhone 5’s 4-inches, and thus less dense. If you want sharper resolution, look for a higher ppi number. 


Smartphones connect to cell networks according to various standards, depending on the carrier. Generally they're grouped under the headings 3G (third-generation cellphone service) and 4G (fourth-generation). 

Most carriers will try and push you toward LTE, a so-called 4G standard. LTE is more than twice as fast as standard 3G as well as more reliable. In fact, it's probably quite a bit faster than your home’s Wi-Fi. You may here a lot about spectrum bands and MHz (Megahertz, a measure of speed on a particular band), but unless you plan on doing a lot of international travelling, the type of LTE is not a primary concern. 

See Also: The Myth Of The Perfect Device

Older handsets may be tied to 3G networks. In the U.S., 3G networks are split into two groups: CDMA and GSM (HSPA+). CDMA is the standard that Sprint and Verizon use. It is an old standard but generally reliable. Its latest evolution before Sprint and Verizon go to LTE is known as WCDMA. AT&T and T-Mobile use GSM, a global standard that offers more flexibility when traveling. Its most recent evolution is HSPA+, which AT&T and T-Mobile liked to call "4G" before AT&T migrated to LTE.

If you are a frequent traveler, you likely want a GSM-capable world phone. In that case, you will want to know what type of antennas are in the device and if it can support spectrum bandwidths in the countris where you are most likely to travel. 


Part 1: The Myth Of The Perfect Device

Part 2: How Much Should You Pay?

Part 3: Which Carrier Should You Choose?

Part 4: What Do Hardware Specs Mean?

Part 5: Which Is Better, Android Or iPhone?

Part 6: What Apps Do You Need?