When Apple announced the new iPad, CEO Tim Cook was quoted as saying the iPad’s GPU was four times faster than Nvidia’s Tegra 3. This is Apple taking on the competition head on. Nvidia has a serious graphics heritage and its Tegra 3 SoC is hugely powerful.
While the iPad’s 5X chip has only a dual-core processor to the Tegra 3’s quad, the 5X has a quad-core GPU. Nvidia’s offering uses a GeForce GPU. In theory, Apple’s multi-core graphics processor should work wonders - but just how wonderful can these wonders be? Three times more wonderful than Tegra 3? This is an important question, as both represent the flagship powerhouses' of currently available tablets.
Before we start, a brief word on how and why we conducted these tests. We were interested in seeing if the GPU was three times faster in real operation, not in benchmarking. After all, people buy tablets to play with them, not watch speed tests and benchmark apps. We figured the five main ways of pushing a GPU would be in rendering a web page, streaming 1080p video, playing a game and running an augmented reality app. Whichever does it smoother and quicker takes the win.
There is a rather irritating issue we encountered with this test, involving screen resolution. Our new iPad has a display with 2048 x 1536 resolution, whereas the Transformer Prime we used is 1280 x 800. This makes testing how each would playback 1080p video impossible without using an external display.
We really wanted to test out high resolution video playback as it was something you would likely do often with a tablet. So we took a 1080p video and dropped its resolution down to 720p to compensate for the Prime’s lower screen res.
Once loaded on to both tablets, we pitted them against each other in a similar speed test. It was 2.9 seconds for the new iPad to start playing back the video and, again, scrolling was instantaneous. For the Prime, it took 0.8 seconds.
One way of circumnavigating the 1080p issue is to make both tablets output the video at that resolution to an external display. Connecting both the Prime and the iPad up to our television set, we pushed out locally stored content from tablet to TV. The result was again absolutely instant and slick playback. What might cause issues isn't Tegra 3 itself, more the way Android handles external displays, which just isn't as straightforward. Still though, actual video itself caused no issues whatsoever.
Another way to test how the GPUs cope with normal tablet situations is to look at how they stream video, both HD and SD. Using a combination of Netflix, iPlayer, Sky Go and HD videos on YouTube, we were able to get a decent idea of how the tablets dealt with content.
Netflix currently streams on tablets in standard definition, particularly irritating given its images and thumbnails just got bumped to Retina display res. We have tried to eliminate any lag created by downloading the content by using a 50mbps fibre optic Virgin Media web connection. This means, other than the tablets themselves, the only thing to get in the way of video playback is Wi-Fi connection. As neither has an ethernet port, the best we could do there was to stand in the same place near the router and make sure nothing else was connected to the network.
So here is what we got. It took the iPad 6 seconds to open up the Netflix application and 6.8 seconds to start playing back video. Scrolling through our test film to various points was so quick it was impossible to time. The Transformer Prime behaved very much the same: set to performance mode, the Netflix application opened up in 5.9 seconds and video began playing back in 7.6 seconds. Scrolling again caused no issues whatsoever.
Sky Go is a slightly more clunky app on Android than iOS but none the less, when it actually came to playing back video, had no issues on either tablet whatsoever, with near instant playback that was impossible to time on both. iPlayer behaved very much in the same way but again wasn't helped by the lack of a decent app on Android.
HD content on YouTube was the part of this test we were most excited about, as it should in theory be putting the GPU under a decent enough load. Sure enough, both managed to load a video in under a second and scrolled instantaneously. In fact no matter what video content we seemed to throw at both tablets, neither struggled in any way.
Loading a web page
One way to push a GPU is to boot up a graphically intensive web page, say something like vimeo.com. We would have liked to go for wechoosethemoon.org, but the fact it is Flash only creates problems for the iPad.
This got us thinking, in reality the differences between what Android and iOS do would make achieving a 4x better performance figure very difficult to test, unless everything was weighted heavily in Apple’s favour - which it presumably was.
Problems aside, Vimeo is a HTML5 powered website with lots of high-quality video. Using Chrome for Android and Safari on iOS, we buffered up the rather beautiful Yosemite HD video. This caused absolutely no problems on either tablet, leaving us suitably impressed with both’s performance and HTML 5 itself.
We wanted to take it further, however, so we loaded up nakshart.com. Powered by HTML 5, the site is like an 3D location-based star map. It is very demanding and definitely lagged up both our iPad and the Transformer.
So who booted it quickest? The iPad managed 7.6 seconds and the Prime 8 seconds. Once loaded, it was a different story, the Asus was very laggy indeed. The iPad, to be fair, was still stuttery enough for it not to be the smooth HTML 5 experience you would expect, but still better than the Prime.
Playing a game
Here is where we can really pit the two GPUs against each other. Using that graphical favourite, Shadowgun, we should be able to get a decent idea how both perform when it comes to gaming.
The quad-core GPU in the new iPad will be under particular stress here but should, theoretically, outdo the GeForce GPU in the Tegra 3. Playing Shadowgun on the Prime is very smooth and the dynamic water effects as well as hi-res textures ensure this is one of the top-looking tablet titles you can download.
On iOS, things are very much the same except for that it appears to load a lot quicker and has a very smooth frame rate. What is different is the anti-aliasing and texture resolution, which govern how smooth edges are and what surfaces in the game look like. Here is where Android takes a clear win.
This said, we don’t think this is as far as gaming can go on tablets. In fact, the likes of Sky Gamblers on the iPad is, to us, as good as it gets. But it doesn’t exist on Android. What does is optimised Tegra applications, which to us suit the more hardcore gamer, say like Backbreaker. This means the iPad might not necessarily be 4x faster for gaming but it will likely suit those who like pick up and play apps a lot better.
Augmented reality apps ask SoCs and GPUs to do all sorts of complex tasks. As well as running the camera application, you need to apply graphics over the top of whatever the sensor is seeing, as well as look at location-based data. It is a demanding process that takes advantage of all the technical wizardry that a tablet provides.
Enter Layar, just about the most established augmented reality app there is in both the App Store and Google Play. From boot, we were looking at 6 seconds to launch the London Tube Layar on the Prime and 3 seconds on the iPad.
Next up we wanted to really overload the tablets, we did this by running Yelp, which brings up all sorts of local businesses and icons on the screen. It was buttery smooth on both tablets.
By this point in our testing we were beginning to realise that Apple’s claim just doesn’t apply in the real world. We were noticing tiny differences in speed between the two but nothing that would constitute a 4x increase. We could see a situation where, if we were to run benchmarking apps, then it could be a four times faster GPU. Then again, who sits with a brand new shiny tablet and just runs benchmarking figures through it?
So when it comes to actually using the Prime or iPad on a daily basis, the difference in speed between the two is negligible. It is the apps and the operating system that are really going to make things smoother for users. To quantify just how smooth this must be is nigh on impossible. What can be said from this test however is that both Tegra 3 and the new iPad are incredibly quick, so much so that it feels like they have hit a slight performance ceiling, with general tablet operation; streaming video or viewing websites, being instantaneous.
What do you think to Apple's claims? Let us know in the comments below ...