Samsung Galaxy S 2 (International) Review - The Best, Redefined
by Brian Klug & Anand Lal Shimpi on September 11, 2011 11:06 AM EST- Posted in
- Smartphones
- Samsung
- Galaxy S II
- Exynos
- Mobile
The Fastest Smartphone SoC Today: Samsung Exynos 4210
Samsung has been Apple's sole application processor supplier since the release of the original iPhone. It's unclear how much Samsung contributes to the design process, especially with later SoCs like the A4 and A5 carrying the Apple brand. It's possible that Samsung is now no more than a manufacturing house for Apple.
Needless to say, the past few years of supplying SoCs for the iPhone and iPad have given Samsung a good idea of what the market wants from an application processor. We first got the hint that Samsung knew what it was up to with its Hummingbird SoC, used in the Galaxy S line of smartphones.
Hummingbird featured a 1GHz ARM Cortex A8 core and an Imagination Technologies PowerVR SGX 540 GPU. Although those specs don't seem very impressive today, Hummingbird helped Samsung ship more Android smartphones than any of its competitors in 2010. At a high level, Hummingbird looked a lot like Apple's A4 used in the iPad and iPhone 4. Its predecessor looked a lot like Apple's 3rd generation SoC used in the iPhone 3GS.
Hummingbird's successor however is Samsung's first attempt at something different. This is the Exynos 4210 application processor:
We first met the Exynos back when it was called Orion at this year's Mobile World Congress. Architecturally, the Exynos 4210 isn't too far from Apple's A5, NVIDIA's Tegra 2 or TI's OMAP 4. This is the same CPU configuration as all of the aforementioned SoCs, with a twist. While the A5, Tegra 2 and OMAP 4 all have a pair of ARM Cortex A9 cores running at 1GHz, Exynos pushes the default clock speed up to 1.2GHz. Samsung is able to hit higher clock speeds either through higher than normal voltages or as a result of its close foundry/design relationship.
Exynos 4210 with its PoP LPDDR2
ARM's Cortex A9 has configurable cache sizes. To date all of the A9 implementations we've seen use 32KB L1 caches (32KB instruction cache + 32KB data cache) and Samsung's Exynos is no exception. The L2 cache size is also configurable, however we haven't seen any variance there either. Apple, NVIDIA, Samsung and TI have all standardized on a full 1MB L2 cache shared between both cores. Only Qualcomm is left with a 512KB L2 cache but that's for a non-A9 design.
Where we have seen differences in A9 based SoCs are in the presence of ARM's Media Processing Engine (NEON SIMD unit) and memory controller configuration. Apple, Samsung and TI all include an MPE unit in each A9 core. ARM doesn't make MPE a requirement for the A9 since it has a fully pipelined FPU, however it's a good idea to include one given most A8 designs featured a similar unit. Without MPE support you run the risk of delivering an A9 based SoC that occasionally has lower performance than an A8 w/ NEON solution. Given that Apple, Samsung and TI all had NEON enabled A8 SoCs in the market last year, it's no surprise that their current A9 designs include MPE units.
NVIDIA on the other hand didn't have an SoC based on ARM's Cortex A8. At the same time it needed to be aggressive on pricing to gain some traction in the market. As a result of keeping die size to a minimum, the Tegra 2 doesn't include MPE support. NEON code can't be executed on Tegra 2. With Tegra 3 (Kal-El), NVIDIA added in MPE support but that's a discussion we'll have in a couple of months.
Although based on Qualcomm's own design, the Snapdragon cores include NEON support as well. Qualcomm's NEON engine is 128-bits wide vs. 64-bits wide in ARM's standard implementation. Samsung lists the Exynos 4210 as supporting both 64-bit and 128-bit NEON however given this is a seemingly standard A9 implementation I believe the MPE datapath is only 64-bits wide. In other words, 128-bit operations can be executed but not at the same throughput as 64-bit operations.
The same designs that implemented MPE also implemented a dual-channel memory controller. Samsung's Exynos features two 32-bit LPDDR2 memory channels, putting it on par with Apple's A5, Qualcomm's Snapdragon and TI's OMAP 4. Only NVIDIA's Tegra 2 features a single 32-bit LPDDR2 memory channel.
| ARM Cortex A9 Based SoC Comparison | ||||||
| Apple A5 | Samsung Exynos 4210 | TI OMAP 4 | NVIDIA Tegra 2 | |||
| Clock Speed | Up to 1GHz | Up to 1.2GHz | Up to 1GHz | Up to 1GHz | ||
| Core Count | 2 | 2 | 2 | 2 | ||
| L1 Cache Size | 32KB/32KB | 32KB/32KB | 32KB/32KB | 32KB/32KB | ||
| L2 Cache Size | 1MB | 1MB | 1MB | 1MB | ||
| Memory Interface | Dual Channel LP-DDR2 | Dual Channel LP-DDR2 | Dual Channel LP-DDR2 | Single Channel LP-DDR2 | ||
| NEON Support | Yes | Yes | Yes | No | ||
| Manufacturing Process | 45nm | 45nm | 45nm | 40nm | ||
Like most of its competitors, Samsung's memory controller does allow for some flexibility when choosing memory types. In addition to LPDDR2, the Exynos 4210 supports standard DDR2 and DDR3. Maximum data rate is limited to 800MHz regardless of memory type.
Based on everything I've said thus far, the Exynos 4210 should be among the highest performing SoCs on the market today. It has the same clock for clock performance as an Apple A5, NVIDIA Tegra 2 and TI OMAP 4430. Samsung surpassed those designs by delivering a 20% higher operating frequency, which should be tangible in typical use.
To find out let's turn to our CPU performance suite. We'll start with our browser benchmarks: SunSpider and BrowserMark:
Despite the 20% clock speed advantage the Galaxy S 2 isn't any faster than Motorola's Droid 3 based on a 1GHz TI OMAP 4430. Unfortunately this doesn't tell us too much since both benchmarks take into account browser performance as well as total platform performance. While the Galaxy S 2 is clearly among the fastest smartphones we've ever reviewed it looks like Motorola's browser may actually be a bit more efficient at javascript execution.
Where we do see big gains from the Exynos' higher clock speed is in our Linpack tests. The single-threaded benchmark actually shows more scaling than just clock speed, indicating that here are other (possibly software?) factors at play here. Either way it's clear that the 20% increase in clock speed can surface as tangible if the conditions are right:
A clock speed advantage today is nice but it's something that Samsung's competitors will be able to deliver in the not too distant future. Where Samsung chose to really differentiate itself was in the graphics department. The Exynos 4210 uses ARM's Mali-400 MP4 GPU.
Shipping in smartphones today we have GPUs from three vendors: Qualcomm (Adreno), Imagination Technologies (PowerVR SGX) and NVIDIA (GeForce). Of those vendors, only Qualcomm and NVIDIA produce SoCs - Imagination simply licenses its technology to SoC vendors.
Both Apple and Intel hold significant amounts of Imagination stock, presumably to protect against an eager SoC vendor from taking control of the company.
ARM also offers GPU IP in addition to its CPU designs, however we've seen very little uptake until now. Before we get to Mali's architecture, we need to talk a bit about the different types of GPUs on the market today.
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tipoo - Sunday, September 11, 2011 - link
The iPhone 4 always scores near the bottom of the 2.0 test since its native resolution is so high, but I'd be interested to know how it does with the resolution independent 2.1 test?B3an - Sunday, September 11, 2011 - link
...but the iPhone 4 is already in the 2.1 tests which are all run at 1280x720 so it's equal on every phone... and unsurprisingly it's the worst performer.Lucian Armasu - Sunday, September 11, 2011 - link
The iPhone 4 has a GPU that is one generation older than the one in the first Galaxy S phone. So that's the main reason why it performs the worst in all these GPU tests.LostViking - Saturday, September 17, 2011 - link
You can do the math already.If you calculate the pixel ratio (width * height) between the iPhone and the others you can correct the numbers.
3lackdeath - Sunday, September 11, 2011 - link
When are you guys going to start adding WP7 to the Comparisons list WP7 is soooo lacking in your reviews.It has been out for a while now you know, a long long time did i say long?.
shamalh108 - Sunday, September 11, 2011 - link
Hi Brian.. first off thanks for the great review..its quite honestly the best I've read on the SGS2..As an SGS2 user i need to just testify to my experience of the AOS bug..
This bug or its effects aren't actually experienced by me while the phone is actually in use, but actually results in a dramatic use of battery when in suspend.. it is intermittent so it won't occur all the time but over the last month I've been able to identify it using battery monitor pro.
what i find is that in the morning when unplugged i can put my edge data on and then leave the phone in standby for up to two hours and see no drain... if i then proceed to use the phone for about 20min and note the battery percentage , i then lock the phone and leave it in standby again with edge data enabled and push email... after closing all tasks but the battery percentage will drop by up to 10% in those two hours while battery monitor pro reports an estimate usage of 100+ mah ..compared to the same running conditions it was in when just unplugged and consumed almost no power. this isn't always the case though sometimes the phone will only drop 2% or less per hour with the battery monitor pro reporting usage of 25~35 mah ... As you can see this bug actually affects standby time more than nonstop usage and that is probably why the benchmarks havent been affected.. also im not sure if its normal but when the phone is experiencing the high usage and i look at the process cpu usage the events and suspend process are consuming around 15~20% cpu... this checked immediately after unlocking the phone using watchdog task manager pro.
while i understand all the measurements are estimates .. i really feel the effects of this as with the same usage i can't be certain if ill get the 14hours battery life i need or 10.. what is the normal power consumption for an android phone in suspend as I've noticed my brothers HTC desire consistently consumes 10~15mah in standby with a similar set up..
again thanks for the great review..
my international SGS2 is running stock with no root , XXKF3 .
willstay - Sunday, September 11, 2011 - link
I have been using SGS2 for two months now and this is my 3rd Android. In the past, I always flashed closest to stock ROM, now after 2 months, I think google should consider touchWiz kindof UI as default. It is really minimalistic with just few tiny bit feature that makes it way better than stock - folders and page scrolling where I can put important apps in page 1, system apps in page 2 and so on.One consistent touchWiz feature to swipe contacts left for message and right for call is a must have.
I must be having over sensitive eye that comfortable brightness level I use during day (indoor) is zero and for evening and night, I am using app called "Screen Filter" to make it dimmer. (I know this is only me - for my laptop I had to hack drivers to make it dimmer than allowed normally).
When idle, processor goes back to 200 MHz and normally with wifi off, cellular net off, SGS2 lives through the night depleting only 1% of the battery. When I only use it for phone and sms, I get two days. Most of the time when I have access to desktop, I turn off wifi and push mail. My usual battery indicator runs as follows - fully charged before going to sleep - 99% when I wake up - I turn wifi and push mail on and by the time I move out to office it is 97% - wifi off in office but sometimes on when I move out of my desk to run SIP client and get my desk extension routed to phone and by lunch time it is 90% - push mail on and cellular net on during lunch time 86% - when I reach home it is from 80 to 75% - that is when my phone gets highest load of games, browsing, wifi, pushmail until I plug for charing around 11 pm and before I plug in it is usally 30%. For comparison, the lowly Nokia 1280 I am using for backup ran for 15 days in single charge and there was still 1/5 bar left in it.
"light weight seems to imply a certain level of cheapness" - people will soon start to understand weight has no correlation with quality and when devices grow bigger and bigger, they will appreciate lighter weight design.
As for me, this is my first Samsung and I am impressed!! Unfortunagely SGS2 has short life it seems - I am so impressed with this light weight, thinness, SAMOLED+, touchWiz that I am getting SG-Note at whatever cost when it comes out :)
shamalh108 - Sunday, September 11, 2011 - link
hey willstay.. wow ! please help me , how are you getting such astonishing battery life ? what Rom are you on ? is your phone used at all during the day ? i simply can not get that kinda standby consumption between my few use periods during the day.. i love my phone and right now its just the battery life that's frustrating me.. why are the reports so varied .. any info you have would be welcome :)ph00ny - Sunday, September 11, 2011 - link
I'm also getting a full day of usage like the user above. I ran stock rom forever until i ventured over to the some of the newer custom roms and i'm getting slightly less battery life with the newest sensation 1.6 rom (2.3.4) compared to stock and cognition 1.07.willstay - Sunday, September 11, 2011 - link
I am using default ROM but flashed kernel for rooting. I guess it must be rouse app. I've found Location And Security -> Use Wireless Networks eats up around 7% of battery through night (which otherwise is only 1%). Sometimes service called MediaService (after I've played songs through Btooth) eats up around 25% through sleep hours. Once I used very nice network bandwidth monitoring app to find individual data usage, it was sipping 25% during sleep hours (I install this app only when I need it). Pushmail on low signal cellular network eats battery like hell - my phone gets warm at the back. Interestingly, always-on low light digital clock of app NoLED eats only 20% through night. For most of the bug related drainage, flushing RAM helps.If I were you, I would temporarily uninstall few apps at a time to find the culprit. You may be able to short list possible apps through battery usage tool of the phone too.