HTC One X: Snapdragon S4 Krait vs. NVIDIA Tegra 3 Comparison

HTC announced their brand new One X flagship cell phone yesterday on Day 0 of the Mobile World Congress convention in Barcelona, Spain. It’s a top contender for the best announced smartphone at the event, stacking itself up proudly against offerings from LG, Sony, and Huawei. The One Series, lined up behind the flagship One X, represent the culmination of HTC’s efforts to conform to their new “Hero” strategy. The international version of the One X, available in Europe “in the coming months” features NVIDIA’s Tegra 3 processor. But, the United States’ version of the device, available exclusively on AT&T, will sport the brand new Snapdragon S4 SoC. Essentially, HTC’s releasing two variants of the device in order to give AT&T users their much-desired LTE modem, which isn’t included (yet) in the Tegra 3 SoC.

How does this switch effect performance? What are the differences between these two next-gen mobile chips? We’ll dive into all that below, comparing their CPU units, graphics processors, modem capabilities, architectures, and battery saving features.

	Qualcomm Snapdragon S4 (AT&T)	NVIDIA Tegra 3 (International)
Architecture	28 nm Cortex-A15 Base	40 nm Cortex-A9 Base
CPU	MSM8960 Krait 1.5 GHz	Tegra 3 1.5 GHz
CPU Cores	Dual-core	Quad-core + companion core
GPU	Adreno 225	ULP GeForce GPU
GPU Cores	8-core	12-core
Modem	HSPA/WCDMA/GSM/GPRS/EDGE/CDMA2000/LTE/1xEV-DO/TD-SCDMA/UMTS	HSPA/WCDMA/GSM/GPRS/EDGE

Qualcomm’s Snapdragon S4, this specific model, is known as “Krait.” The Krait CPU has a recommended clock between 1.5 and 1.7 GHz. Of course, it’s a dual-core CPU. But, that doesn’t mean it’s slower than the Tegra 3′s quad-core (plus companion core) chip. In fact, the 28-nanometer design behind the Snapdragon S4 allows those two cores to run more efficiently. According to the benchmarking extraordinaires over at AnandTech, the dual-core Snapdragon S4 actually bests the NVIDIA Tegra 3′s quad-core CPU in most tests.

Here’s an aggregation of the benchmark scores for the two CPUs.

	MSM8960 Krait 1.5 GHz	Tegra 3 1.5 GHz
SunSpider Javascript Benchmark*	1532	1712
BrowserMark	110,345	108,845
Linpack Single-threaded	106.794	54.514
Linpack Multi-threaded	218.197	156.827

* Lower is better.

As you can see, the Krait chip had no problems keeping up with the Tegra 3 in benchmark tests. The difference here lies in the Cortex-A15 architecture behind the Snapdragon S4. The Cortex-A15 boasts 40% speed improvement over its Cortex-A9 predecessor when boiled down to the same number of cores and same clock speeds. Of course, the marks are too close to call the match for either chip. But, we’ll have to look at real world experiences with each chip for more guidance.

Here’s where NVIDIA has the big advantage. The Tegra 3 ULP GeForce GPU is an upgraded version of the Tegra 2′s GeForce graphics processor, and packs an incredible 12-core setup. The Tegra 3 GPU includes support for 3D stereo, Open GL ES 2.0, OpenVG 1.1, and EGL 1.4. Meanwhile, our Adreno 225 (in the Snapdragon S4)  supports Open GL ES 2.0 as well as DirectX 9.3 (on Windows 8). The Tegra 3′s GeForce GPU offers three times the performance over its predecessor, the Tegra 2.

Let’s check out the performance benchmarks for the GPU. Note: the best benchmarks to look at are probably the GLBenchmark 2.1 tests, which are equaled out on two 720p external displays.

	Adreno 225	ULP GeForce (Tegra 3)
AN3DBenchXL	38,786	36,436
NenaMark 2	59.9	45.3
GLBenchmark 2.1 – Egypt – Offscreen 720p	52.2	64.4
GLBenchmark 2.1 – Pro – Offscreen 720p	62.2	78.4
Basemark Taiji	40.576 (1024 x 600)	15.8 (1024 x 768)
Basemark Hoverjet	59.586 (1024 x 600)	28.6 (1024 x 768)

NVIDIA’s Tegra 3 boasts a fifth “companion core” that utilizes LP transistors to save battery during relatively inactive CPU states.  That means if you need a phone to last a long period of time on standby (when the screen’s off), the Tegra 3 should be beneficial.

Meanwhile, the Snapdragon S4 includes a brand new integrated SoC with the LTE connectivity built-in. According to Qualcomm, this LTE modem will share resources with the processor and save battery consumption. NVIDIA plans on releasing a modified Tegra 3 chip with integrated LTE later this year.

Both versions of the HTC One X should offer similar performance, with two very fast chips behind their speedy performance. Based on the specifications and benchmark tests, the edge goes to the Snapdragon S4 in the CPU department, while the Tegra 3 takes the GPU trophy. It’s fair to say that the Tegra 3 version of the One X will be optimal for next-gen gaming and entertainment, while the Krait-powered One X offers the upperhand otherwise.

The most surprising thing about this comparison is just how similar these chips perform although they’re completely different in terms of architecture and core numbers. Don’t for a second discount a phone just because it has fewer cores. It’s safe to say that both of these SoC’s will perform admirably on Android 4.0 Ice Cream Sandwich, offering mobile enthusiasts never before seen performance