Display
iPhone 5S
The 5S features a 4-inch 1,136 x 640 Retina display with a pixel density of 326 pixels per inch, a brightness rating of 500 nits and an 800:1 contrast ratio. However, it was surprising that that Apple kept the same 1136×640 pixels resolution, while most smartphones in that price range have moved to 1080p:1920×1080 (2,073,600 pixels). Though it means that the competing devices have nearly 3X more pixels than the iPhone, in terms of visual quality and sharpness the iPhone 5S is second to none.
Overall, the 5S's display is excellent. It shows vibrant and bright colours on webpages, games and video. Similarly, the text is clean and crisp. The high-quality in-plane switching (IPS) panel remains evenly lit and gives impressive viewing angles, meaning you can see what's on screen whether looking down from the top, up from the bottom, front or side on, or anywhere in between.
Nexus 5
The Google Nexus 5 has a 4.95 inch 1080 x 1920 True HD IPS+ display which results in a pixel density of 445 pixels per inch. Not surprisingly, it is hard to notice the difference between pixel density on both Nexus 5 and iPhone 5S unless you go nose-to-screen, but Nexus 5 wins here in terms of higher resolution.
The Nexus 5' LCD panel delivers great color quality, as you would expect from the IPS technology used. The colors are realistic and eye-catching. The device offers great contrast levels, giving strong untinted white levels and deep blacks. The Nexus 5 offers good viewing angles, keeping the display readable in a variety of situations. The 1080p display really comes in handy while reading text, due to the extra level of display it offers. Besides, a resolution of 1920 x 1080 means you can watch Blu-ray-quality videos without a loss in detail from upscaling or downscaling, so the crispness transfers to movies as well.
Winner: Nexus 5
Processor
iPhone 5S
Apple has packed the iPhone 5S with a new A7 dual-core chip based on 64-bit architecture along with 1 GB of RAM. On paper, the iPhone 5S has a 1.3GHz dual-core processor based on ARM's 28-nanometer ARMv8 architecture, with a new 64-bit instruction set, wider registers, and a larger cache. Apple says the new A7 chip is up to twice as fast as the A6 in both processing and graphics. Although Apple's dual-core chip may sound quaint, tests demonstrate that more cores do not necessarily equal better performance. In tests for both CPU and GPU performance, the iPhone 5s beat out every phone it was up against, by a handsome margin.
For graphics, Anandtech found the A7 to contain a PowerVR G6430 GPU that supports OpenGL ES version 3.0, which Apple is claiming to be twice as fast as the prior generation iPad 4.
Apple's iPhone 5s also comes with a new "M7" chip that is otherwise known as a "motion coprocessor." It is designed to work alongside the A7 processor, capturing motion data from the phone's compass, accelerometer, and gyroscope to power a new generation of health and fitness apps. Alongside the M7 chip, the company has also offered new CoreMotion APIs that can take advantage of the M7 coprocessor to create improved fitness and activity apps that are unavailable on similar devices. The M7 coprocessor can measure and track all movement data, even when the phone is asleep. So, now fitness apps that track physical activity can access that data from the M7 coprocessor without constantly engaging the A7 chip. So they require less battery power.
Nexus 5
The Nexus 5 features Qualcomm-made system-on-a-chip (SoC), which includes a 2.3 GHz quad-core Krait 400 CPU, 450 MHz Adreno 330 GPU, Hexagon QDSP6V5A DSP at 600 Mhz, an LTE modem block, Bluetooth 4.0 and GPS+GLONASS. It also has a 2 GB of LPDDR3-1600 RAM on a dual-channel 800 MHz bus, which is standard for Snapdragon 800 devices and provides 12.8 GB/s of bandwidth.
All these hardware stuff along with improvements in the touchscreen responsiveness makes the Nexus 5 offer the smoothest Android experience. It makes multi-tasking and web browsing really fast, and with KitKat re-engineered for speed, gaming is a blast on the device. Further, you won't expect a single crash or hiccup when scrolling around menus.
In benchmarking tests, on AnTuTu, the Nexus 5 scored a 26010, falling short of G2's champion score of 34191, but still a respectable figure. On Geekbench 3, it racked up a score of 2767, performing better than LG G2 and the HTC One.
Though the Nexus 5 has 2GB of RAM as against the iPhone 5s' 1GB, the 5S's processor has much more capability to perform.
Winner: Draw
