Since the Krait 450 complex in Snapdragon 805 is architecturally the same as Snapdragon 800/801's Krait 400, their relative CPU performance should scale based on clock rate.
For reference, the 805 has an 8% advantage over 801 (2.65 versus 2.45 GHz) and 17% over 800 (2.65 versus 2.26 GHz). While Snapdragon 805 has a significant memory bandwidth advantage, the CPU isn’t starved for data in the 800/801. Therefore, this shouldn’t have a significant influence on the CPU benchmarks.
AnTuTu is an Android system benchmark designed to test the performance capabilities of four major aspects of mobile devices: Graphics (encompassing 2D, UI, and basic 3D), CPU (fixed, floating-point, and threading), RAM (read and write), and I/O (read and write).
Our first CPU benchmark's RAM test highlights the 805’s improved memory bandwidth, achieving its theoretical advantage over the 801. The 805, however, doesn’t fare as well in the other sub-tests. Qualcomm's Adreno 420 engine turns in the lowest GPU test score for both 2D and 3D graphics. Its 3D result is actually 15% slower than Nvidia’s GeForce ULP in the Tegra 4 (the 3D graphics winner in this benchmark). The 805's Krait 450 CPU also finishes last in the CPU test, where its score is 35% lower than the category-winning 801.
Basemark OS II
Basemark OS II is an all-in-one tool designed for measuring the overall performance of mobile devices. It scores each one in four main categories: System, Memory, Graphics, and Web. The System score reflects CPU and memory performance, specifically testing integer and floating-point math, along with single- and multi-core CPU image processing using a 2048x2048, 32-bit image. Measuring the transfer rate of the internal NAND storage (Memory) is done by reading and writing files with a fixed size, files varying from 65 KB to 16 MB, and files in a fragmented memory scenario. Calculating the Graphics score involves mixing 2D/3D graphics inside the same scene, applying several pixel shader effects, and displaying 100 particles with a single draw call to test GPU vertex operations. The benchmark is rendered at 1920x1080 off-screen 100 times before being displayed on-screen. Finally, the Web score stresses the CPU by performing 3D transformations and object resizing with CSS, and also includes an HTML5 Canvas particle physics test.
The Basemark OS II Graphics test shows a complete reversal. Qualcomm's Adreno 420 posts the highest score as Nvidia's Tegra 4 finishes last. Isolating Snapdragon processors, the 805 is 22% faster than the 801 and 28% faster than the 800.
Similarly, the 805 outpaces the 801 and 800 in this benchmark's Web test by 3% and 23%, respectively, which is pretty close to their clock rate differences. In the CPU-oriented System metric, the 805 turns in a score 11% lower than the 801 and is only 6% faster than the 800. It’s curious that the 805 performs as expected in the CPU-bound Web test, but underperforms in the System test. So far, the theme for the 805’s CPU performance is inconsistency.
Geekbench 3 Pro
Primate Labs' Geekbench offers a wide selection of cross-platform compatibility, with apps available for Windows, OS X, Linux, iOS and Android. This simple system benchmark produces two sets of scores: single- and multi-threaded. For each, it runs a series of tests in three categories: Integer, Floating Point, and Memory. The individual results are used to calculate category scores, which, in turn, generate overall Geekbench scores.
In the Single-Core benchmark, we see Snapdragon 805 finish 8.6% higher than the 801 and 11% higher than the 800. The scores don’t exactly scale according to frequency, suggesting the software is encountering some other bottleneck. Looking at the margin of victory for Apple’s A7 SoC, it appears that Geekbench 3 Pro prefers the A7’s higher IPC and larger caches to Snapdragon’s higher clock rate.
Once again, we record inconsistent performance from Qualcomm's Snapdragon 805. Even with half as many cores, Apple’s A7 outscores it, as do both previous-generation Snapdragons. While the 805 cruises to victory in the Multi-Core Memory test (as expected), it’s 9% slower than the 801 in Multi-Core Floating Point and a surprising 21% slower in Multi-Core Integer.
Since our time with the 805 was limited during a hands-on benchmarking event with Qualcomm, we didn’t have an opportunity to dig into these results. However, because the 805’s score is greater than half of the 801, it’s safe to assume that all four cores were active during the tests. The most reasonable explanation then is that the 805 isn’t achieving its peak frequency when all four cores are active. This might explain the inconsistencies in the other CPU benchmarks too, as some focus more on single-core performance (like the benchmarks based on Web browsing) and some stress multiple cores (AnTuTu CPU and Basemark OS II System).