Original Link: http://www.anandtech.com/show/4215/apple-ipad-2-benchmarked-dualcore-cortex-a9-powervr-sgx-543mp2



The second generation iPad went on sale earlier today, to much fanfare and long, long lines. We're hard at work on our full review of Apple's second generation tablet but there were a few things we wanted to chime in on before too much time passed.

The iPad 2 is a very logical update to the original iPad. The hardware gets an upgrade, with revised industrial design, a slimmer chassis, and Apple's new A5 SoC inside. A5 brings along two Cortex A9 cores, a dual core version of PowerVR's SGX543 graphics chip, and 512MB of memory. Software stays mostly the same but gets some tweaks; the iPad 2 ships with iOS 4.3, which was released earlier this week as an update for the iPhone 4 and original iPad.

The industrial design has changed pretty significantly, from the convex curvature of the original iPad's back to the flat back of the new iPad. Starting with the iPhone 4, Apple has been moving away from the continuous curvature that dominated their handhelds two or three years ago (think iPhone 3G/3G-S, iPod touch 2G/3G, and the 4G/5G iPod nano) and more towards a flatter and more rectangular design language across the board. The iPhone 4 is the only one that's really angular, but the 4th generation iPod touch debuted the same flatness with more ergonomically friendly curves. The iPad 2 basically carries the iPod touch 4G design language on a larger scale.

The iPad 2 is slightly lighter but easier to hold than the previous generation. Laying in bed and reading is probably where the difference becomes most apparent. The gentle curvature running around the edge makes the in-hand feel surprisingly different, as does the considerably thinner profile. I'm actually shocked at how dramatic the difference is.

The downside to the very large radius curvature on the outside is that the dock connector is now awkwardly exposed. It's very similar to how the iPod Touch looks, with about 2 mm of exposed connector visible viewed from the back.

The previous generation dock connector was the subject of constant criticism for being way too tight. Apple has over-corrected with the iPad 2 and now the dock connector is too loose. Just browsing the Apple store, I noted several units whose dock connectors appeared plugged in, but had come just loose enough to not charge.

When connecting 30-pin dock cables, there's not too much resistance holding the cable in place, and the port itself is difficult to locate without flipping the thing over or viewing it from below.

Another welcome change - the return of the white iDevice. After the no-show that was the white iPhone 4, I was pleased to see Apple ship the white-bezeled iPad 2 on time with no production hitches. I was also wrong about how good white would look. Instead of being overwhelming or busy, the white bezel actually has one notable advantage over black - it doesn't show fingerprints or dust. That alone was what constantly drove me crazy about the previous generation - it always looked dirty. Shockingly, white seems to actually make sense.

 

Other hardware chances are the addition of front and rear facing cameras for FaceTime and taking pictures, but unfortunately, they seem to be pieces lifted from the iPod touch and nothing near the iPhone 4's 5 megapixel shooter. We'll talk about what this means for picture quality overall later on in the preview. The switch on the side can now be configured to either be a device silencer or a rotation lock switch, and there is now a large speaker on the bottom right corner of the device.

Overall, the new design really works - the iPad 2 feels good in hand, and instantly makes its predecessor feel a little clunky. But we didn't just pause our testing to talk about design, there's a lot under the hood of the iPad 2 that demands attention.



I remember the speculation that lead up to Apple's iPad launch. The list of things everyone expected the device to do was absurd, and the theories on the architecture behind Apple's first branded SoC was just as fantastic. The simplest answer is sometimes the right one and as Ars Technica's Jon Stokes pointed out, the A4 was nothing more than a hardened ARM Cortex A8 core running at 1GHz in the iPad (and 800MHz in the iPhone 4).

The Cortex A8 is something we've covered extensively here so I won't go into great detail right now. It's a dual-issue, in-order architecture with a 13 stage integer pipeline and a non-pipelined FPU.

When Apple announced the iPad 2, it also briefly announced the A5 SoC. The only detail given? The A5 is a dual-core processor with a GPU that's 9x faster than what's in the A4.

There are only two recent ARM architectures that have multicore support: the ARM11 and the ARM Cortex A9. The A8 doesn't come in a multicore variant. Given how many other SoC vendors are shipping dual-core Cortex A9 SoCs, the A5 was likely no different than NVIDIA's Tegra 2, TI's OMAP 4 or Samsung's Exynos in that regard: armed with a pair of Cortex A9s running at 1GHz. Update: Geekbench reports clock speed at 900MHz. Update 2: Apple confirms 1GHz clock speed on the iPad 2 specs page.

Architecture Comparison
  ARM11 ARM Cortex A8 ARM Cortex A9 Qualcomm Scorpion
Issue Width single-issue dual-issue dual-issue dual-issue
Pipeline Depth 8 stages 13 stages 9 stages 13 stages
Out of Order Execution N N Y Partial
FPU Optional VFPv2 (not-pipelined) VFPv3 (not-pipelined) Optional VFPv3-D16 (pipelined) VFPv3 (pipelined)
NEON N/A Y (64-bit wide) Optional MPE (64-bit wide) Y (128-bit wide)
Process Technology 90nm 65nm/45nm 40nm 40nm
Typical Clock Speeds 412MHz 600MHz/1GHz 1GHz 1GHz

The Cortex A9 is similar to the A8 but with an out-of-order execution engine and a shallower pipeline (9 stages). The result is better-than-A8 performance at the same clock speed. The A9 also adds a fully pipelined FPU.

Now it's unclear what the rest of the A5 SoC looks like, but from the CPU standpoint I think it's safe to say that there are a pair of ARM Cortex A9s in there. We can look at the increase in Geekbench Floating Point scores for some proof:

Geekbench 2 - Floating Point Performance
  Apple iPad Apple iPad 2
Overall FP Score 456 915
Mandlebrot (single-threaded) 79.5 Mflops 279.1 Mflops
Mandlebrot (multi-threaded) 79.4 Mflops 554.7 Mflops
Dot Product (single-threaded) 245.7 Mflops 221.7 Mflops
Dot Product (multi-threaded) 247.2 Mflops 436.8 Mflops
LU Decomposition (single-threaded) 54.5 Mflops 205.4 Mflops
LU Decomposition (multi-threaded) 54.8 Mflops 421.6 Mflops
Primality Test (single-threaded) 71.2 Mflops 177.8 Mflops
Primality Test (multi-threaded) 69.3 Mflops 318.1 Mflops
Sharpen Image (single-threaded) 1.51 Mpixels/s 1.68 Mpixels/s
Sharpen Image (multi-threaded) 1.51 Mpixels/s 3.34 Mpixels/s
Blur Image (single-threaded) 760.2 Kpixels/s 665.5 Kpixels/s
Blur Image (multi-threaded) 753.2 Kpixels/s 1.32 Mpixels/s

Single threaded FPU performance is multiples of what we saw with the original iPad. This sort of an improvement in single-core performance is likely due to the pipelined Cortex A9 FPU. Looking at Linpack we see the same sort of huge improvement:

Linpack

Whether this performance advantage matters is another matter entirely. Although there aren't many FP intensive iPad apps available today, moving to the A5 is all about enabling developers - not playing catch up to software.

Memory size, bandwidth and operating frequencies are all unknowns that I was hoping to find out more about once I put hands on the iPad 2. Geekbench reports the iPad 2 at 512MB of memory, double the original iPad's 256MB. Remember that Apple has to deal with lower profit margins than it'd like with the iPad, but it refuses to cut corners on screen quality so something else has to give.

L2 cache size has also apparently increased from 512KB to 1MB. The L2 cache is shared among both cores and 1MB seems to be the sweet spot this generation.

Geekbench 2 - Memory Performance
  Apple iPad Apple iPad 2
Overall Memory Score 644 787
Read Sequential (single-threaded scalar) 340.6 MB/s 334.2 MB/s
Write Sequential (single-threaded scalar) 842.4 MB/s 1.07 GB/s
Stdlib Allocate (single-threaded scalar) 1.74 Mallocs/s 1.86 Mallocs/s
Stdlib Write (single-threaded scalar) 1.20 GB/s 2.30 GB/s
Stdlib Copy (single-threaded scalar) 740.6 MB/s 522.0 MB/s

Geekbench's memory tests show an improvement in effective bandwidth as well. The biggest improvement is in the stdlib write test which shows a near doubling of bandwidth from 1.2GB/s to 2.3GB/s. Unfortunately this isn't enough data to draw conclusions about bus width or DRAM operating frequency. Given the increases in CPU and GPU performance, an increase in memory bandwidth to go along with the two isn't surprising.

Geekbench shows a healthy increase in integer performance, both in single and multithreaded scenarios. The multithreaded advantage makes sense (two are better than one), but the lead in single threaded tests shows the benefit the A9 can deliver thanks to its shorter pipeline and ability to reorder instructions around stalls.

Geekbench 2 - Integer Performance
  Apple iPad Apple iPad 2
Overall FP Score 365 688
Blowfish (single-threaded) 13.9 MB/s 13.2 MB/s
Blowfish (multi-threaded) 14.3 MB/s 26.1 MB/s
Text Compression (single-threaded) 1.23 MB/s 1.50 MB/s
Text Compression (multi-threaded) 1.20 MB/s 2.82 MB/s
Text Decompression (single-threaded) 1.11 MB/s 2.09 MB/s
Text Decompression (multi-threaded) 1.08 MB/s 3.28 MB/s
Image Compress (single-threaded) 3.36 Mpixels/s 3.79 Mpixels/s
Image Compress (multi-threaded) 3.41 Mpixels/s 7.51 Mpixels/s
Image Decompress (single-threaded) 6.02 Mpixels/s 6.68 Mpixels/s
Image Decompress (multi-threaded) 5.98 Mpixels/s 13.1 Mpixels/s
Lua (single-threaded) 172.1 Knodes/s 273.4 Knodes/s
Lua (multi-threaded) 171.9 Knodes/s 542.9 Knodes/s

On average Geekbench shows a 31% increase in single threaded integer performance over the A4 in the original iPad. NVIDIA told me they saw a 20% increase in instructions executed per clock for the A9 vs. A8 and if we remove the one outlier (text decompression) that's about what we see here as well.

Geekbench 2
  Overall Integer FP Memory Stream
Apple iPad 448 365 456 644 325
Apple iPad 2 750 688 915 787 324

The increases in integer performance and memory bandwidth are likely what will have the largest impact on your experience. The fact that we're seeing big gains in single as well as multi-threaded workloads means the performance improvement should be universal across all CPU-bound apps.

What does all of this mean for performance in the real world? The iPad 2 is much faster than its predecessor. Let's start with our trusty javascript benchmarks: SunSpider and BrowserMark.

SunSpider Javascript Benchmark 0.9

Apple improved the Safari JavaScript engine in iOS 4.3, which right off the bat helped the original iPad become more competitive in this test. Even with both pads running iOS 4.3, the iPad 2 is 80% faster than the original iPad here.

The Motorola Xoom we recently reviewed scored a few percent slower than the iPad 2 in SunSpider as well. Running different OSes and browsers, it's difficult to conclude much when comparing the A5 to Tegra 2.

A bug in BrowserMark kept us from running it for the Xoom review but it's since been fixed. Again we're looking at mostly JavaScript performance here. Rightware modeled its benchmark after the JavaScript frameworks and functions used by websites like Facebook, Amazon and Gmail among others. The results are simply one aspect of web browsing performance, but an important one:

Rightware BrowserMark

The move from the A4 in the iPad 1 to the A5 in the iPad 2 boosts scores by 47%. More impressive however is just how much faster the Xoom is here. I suspect this has more to do with Google's software optimizations in the Honeycomb browser than hardware, but let's see how these tablets fare in our web page loading tests.

We debuted an early version of our 2011 web page loading tests in the Xoom review. Two things have changed since then: 1) iOS 4.3 came out, and 2) we changed our timing methods to produce more accurate results. It turns out that Honeycomb's browser was stopping our page load timer sooner than iOS', which resulted in some funny numbers when we got to the 4.3/Honeycomb comparison. To ensure accuracy we went back to timing by hand (each test was repeated at least 5 times and we present an average of the results). We also added two more pages to the test suite (Digg and Facebook).

2011 Page Load Test - Average

The iPad 2 generally loads web pages faster than the Xoom. On average it's a ~20% increase in performance. I wouldn't say that the improvement is necessarily noticeable when surfing most sites, but it's definitely measurable.

The move to iOS 4.3 really narrowed the gap between the original iPad and the Xoom. In some cases the two actually render pages in the same amount of time, however that's typically for lighter pages that are easy to render. Up the complexity and the Xoom easily distances itself from the original iPad.

2011 Page Load Test - AnandTech.com

2011 Page Load Test - Amazon.com

2011 Page Load Test - CNN.com

2011 Page Load Test - Digg.com

2011 Page Load Test - Engadget.com

2011 Page Load Test - Facebook.com

2011 Page Load Test - NYTimes.com

2011 Page Load Test - Reddit.com

We'll touch on this more in the full review but it's not all about performance when talking about web browsing between the iPad 2 and the Xoom. Although the iPad 2 may have faster render times on average, the Xoom still supports tabbed browsing which definitely has its advantages.



The GPU: PowerVR SGX 543MP2

There are no spoilers here but the PowerVR SGX 535 in the original A4 is out, replaced by the new PowerVR SGX 543MP2. The 543 as a building block has a bit over twice the peak floating point throughput of the SGX 535. The MP2 just means there are two of these 543s working in tandem. The result is what Apple uses as the basis for their "9x faster" GPU claims. In practice the improvement should be less than that, but it's still enormous.

We've got GPU performance data coming, but I thought I'd take a slightly different route and show what one developer is using the extra horsepower offered by the A5 for.

Epic Games is a familiar face around these parts. We've used games powered by their Unreal Engine in our reviews for years now. More recently Epic has made a splash in the iOS world with the release of its Citadel demo and eventually Infinity Blade.

In time for the launch Epic updated Infinity Blade to have some special enhancements for iPad 2 owners. Rather than simply deliver a higher framerate for iPad 2 users, Epic enabled higher resolution textures and anti-aliasing. The resulting boost in image quality is astounding, particularly on the iPad 2's 1024 x 768 screen:


Mouse over to see Infinity Blade on the iPad 2

The gallery below has a bunch of side by side shots showing the improvements made to Infinity Blade for the iPad 2 vs. what you get when you run the game on a first generation iPad.

As we mentioned before, the A5 (and iPad 2) are about enabling developers. In a year's time the PowerVR SGX 543MP2 will be found in the majority of iOS tablets on the market - and games are just going to get prettier from there.

Update: We've published a look at the performance of the PowerVR SGX 543MP2 running GLBenchmark 2.0 here. If you want a teaser, it's good:



The Display: Multiple Vendors, Nearly Identical to iPad 1

Apple built the iPad 2 with a similar 9.7-inch 1024 x 768 IPS panel as the original iPad. Side by side the two panels appear to have similar qualities in terms of brightness, black level and contrast ratio. Once we started measuring however we noticed a trend: there appear to be multiple panel vendors in play here.

Between Brian, Vivek, Manveer and myself we have four iPad 2s. Brian and I have two 3G models (AT&T and Verizon), while Vivek and Manveer have two WiFi models. All four are white and all four have 16GB of NAND. The results from our baseline display testing are below:

Display Quality Comparison
  White Level Black Level Contrast Ratio
Apple iPad 2 #1 (AT&T 3G) 406 nits 0.42 nits 966:1
Apple iPad 2 #2 (VZW 3G) 409 nits 0.49 nits 842:1
Apple iPad 2 #3 (WiFi) 352 nits 0.45 nits 778:1
Apple iPad 2 #4 (WiFi) 354 nits 0.41 nits 859:1

There seem to be two different values for white level: either around 400 nits or 350 nits. Black level is pretty variable between 0.41 nits and 0.49 nits, there doesn't seem to be a correlation between white and black levels in our admittedly limited sample size. For our display graphs we simply averaged all four together:

Display Brightness

Display Brightness

Display Contrast

On average the iPad 2 seems to be marginally brighter with a bit worse black levels than the original iPad, resulting in a lower contrast ratio. The display is pretty close to what was in the original iPad and very tough to tell apart. There's still a visible advantage in contrast ratio over the Motorola Xoom.



WiFi + AT&T 3G

The iPad 2 uses what boils down to same exact same 802.11a/b/g/n WiFi + Bluetooth 2.1 EDR solution as its predecessor, the BCM4329. The iPad 2 maintains full 5 GHz (802.11a/n) support, just like the previous iPad, and also negotiates a transmit rate of 65 megabits/s just like nearly all single stream 802.11n mobile devices we've seen thus far. Close to the AP and within good coverage radius, the experience is exactly the same as its predecessor. Best case throughput is virtually identical between the two generations.


The black plastic strip at the top still is an RF window for cellular connectivity. The strip is black even if your iPad is white, which is a bit puzzling.

That said, thus far we've noticed that wireless range on the iPad 2 is measurably less than the iPad 1. It's not a terribly huge difference, but definitely noticeable as you drop one or two bars of WiFi signal strength. Throughput goes way down compared to the previous generation. We're still testing everything, but it's just not quite as good. No doubt the iPad 2 has a completely different RF design than the original iPad which accounts for this difference. 

 
Left: iPad 1 across the street, Right: iPad 2 same location

We've got both an AT&T, Verizon, and WiFi model between the three of us (Anand, Vivek, and myself) and will do the usual due diligence testing cellular connectivity.

Following the rather controversial and inexplicable crippling of HSUPA on the Motorola Atrix and Inspire 4G, the first thing I did with the iPad 2 is run a speedtest. HSUPA is definitely enabled on this device and working just fine. Throughput is where it should be in the best and worst signal cases so far, topping out at around 6 Mbps down, 1.5 Mbps up at my house within line of sight to an AT&T Node B. Apparently AT&T is inexplicably only concerned with Android devices crippling the network with upstream traffic.


AT&T iPad 2 Cellular Data Throughput

Anand did some initial testing on the Verizon iPad 2 and averaged 1.54 Mbps down, 0.72 Mbps up in testing with good signal strength, which seems about average. Max speeds we've seen on Verizon so far are 1.64 Mbps down and 0.82 Mbps up.

iPad 2 - Network Support
Verizon Version - CDMA2000-1xEV-DO 800 / 1900 MHz
AT&T Version - Quad-Band UMTS + HSDPA/HSUPA 850 / 900 / 1900 / 2100 MHz
AT&T Version - Quad-Band GSM/EDGE 850 / 900 / 1800 / 1900 MHz
Baseband Hardware Unknown - Possibly MDM6x00

Nobody has disassembled an iPad 2 with 3G connectivity from either Verizon or AT&T, but it seems likely that the two would both leverage a Qualcomm MDM6x00 baseband (where x is 6 for CDMA2000/EV-DO + UMTS/GSM support, 2 for only UMTS/GSM) considering its use in the Verizon iPhone 4.

MicroSIM peeking out of the side on the AT&T version. Also yes, it does come with a SIM ejector tool.

Interestingly enough the AT&T model with FCC ID BCG1396 has UMTS/HSDPA/HSUPA support for quad-band UMTS and GSM. The Verizon FCC ID BCG1397 has reports for just cellular and PCS - 850 and 1900 again but CDMA nomenclature.



Camera

Probably the only major disappointment about the iPad 2 is the cameras, oh the cameras. They're identical to the two cameras in the latest generation iPod touch, and are overall something of a disappointment.

The rear facing camera is a native 1280x720 when shooting video, which crops down to 960x720 (4:3) when taking stills. All the camera app does is toss away 160 pixels on the left and right side when taking still images. There's no autofocus at all, it's just fixed focus, meaning taps on the display simply change exposure. Change to video and you'll see magnification preserved entirely. It's obvious this back sensor was chosen with the intention of shooting video given its apparent native 1280x720 resolution.

 
Left: Still mode, Right: Video capture mode

The iPad 2 camera reminds me of the iPhone 3G camera. It's less impressive than the iPhone 3GS camera which had autofocus and relatively decent image quality, and positively destroyed compared to the iPhone 4 camera system.

iPad 2 front facing camera - Above it is the ambient light sensor

The front camera is actually similar to what we've seen before out of all the iDevice front facing cameras - it's VGA with equally ok performance. White balance seems off inside the light box we use for smartphone testing, as the test images have a distracting reddish cast.

Stills on the rear camera aren't impressive at all, and what makes it worse is that the images are noticeably blurry and noisy when upscaled to the iPad's native XGA resolution. I was shocked to see that the camera preview scales both the front and back camera images all the way up. It looks downright hilarious in person and shows off everything bad about those two cameras.

Video quality is almost exactly the same as the iPod Touch (latest gen with cameras). It's actually pretty good, though I want to do more testing before passing judgement. It's still 720P H.264 Baseline L3.1 at 29.97 FPS. Our demo video is 10.8 Mbps. 

The microphone location for the iPad 2 is (at least on the 3G version) right in the middle of the plastic RF window. It's a super small little port with mesh grating. I found out the hard way that it's also right where you want to hold the iPad naturally, and covered it with my hand in the video above. Apologies about the noise.

iPad 2 microphone in the middle of RF window

What I like about Apple is that usually their UI is some of the most carefully thought out around. Nine times out of ten, it's almost shockingly intuitive, and clearly carefully thought-out. Look no further than how the original iPad's mail app layout has become the most emulated landscape UI design ever.

That said, it's that one time out of ten when things go awfully, terribly, shockingly wrong - sadly, that's precisely what happened in the camera app. The problem is that the camera control bar moves when the iPad is rotated. Yes, it moves. Contrast that to the iPhone and iPod Touch where the bar never moves, and the capture button is always on the bottom near the home button - icons rotate, but the whole bar doesn't move. On the iPad 2, icons rotate, and the whole bar moves.

 
Left: Portrait, Right: Landscape - Note how the capture button is always at the bottom

In both landscape and portrait view, the capture button goes to the bottom of the screen, dead center. In portrait, it's not too hard to just stretch the thumb and tap capture. It isn't comfortable, but it's doable. In landscape however, you either need to either hold the iPad 2 with one hand and tap the capture button with a free hand (which is a great way to accidentally drop the thing or introduce biblical amounts of camera shake), or stretch your thumb to the max and hope to goodness it's long enough to reach the button. In both portrait and landscape, putting the capture button at the bottom is undeniably awkward. This could've been the perfect opportunity to introduce a transparent capture button mid-screen on the sides where the thumbs could naturally tap. Instead, we're left with the most awkward position possible.

To Be Continued...

We couldn't help but share some of our initial thoughts/impressions with you guys but there's still much more to do. Battery life is next on the to-do list along with our continued hunt for a greater understanding of Apple's iPad 2. Check back next week for our full review!

 

 

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