WiFi & GPS

The WiFi stack gets an update with the new iPad courtesy of Broadcom's 65nm BCM4330, compared to the BCM4329 used in the previous two iPads. Both 2.4GHz and 5GHz operation are supported, although as I mentioned earlier the carrier-dependent personal hotspot is only available over 2.4GHz.

As with most smartphone/tablet designs the BCM4330 only supports a single spatial stream, for a maximum link speed of 72Mbps. Similar to the iPad 2, Apple hides the WiFi antenna behind the speaker grille at the bottom of the tablet. The cellular antennas (there are now two) are at the top of the tablet, behind the plastic RF window.

WiFi Performance Comparison
Distance from AP 3 feet 20 feet (Different Room) 50 feet (Different Room/Floor) 100 feet (Different Room)
ASUS TF Prime (2.4GHz) 26.9 Mbps 9.85 Mbps 13.5 Mbps 2.20 Mbps
Apple iPad 2 (2.4GHz) 35.1 Mbps 29.9 Mbps 26.9 Mbps 10.6 Mbps
Apple iPad 3 (2.4GHz) 35.1 Mbps 29.9 Mbps 27.9 Mbps 9.98 Mbps
Apple iPad 2 (5GHz) 36.7 Mbps 36.7 Mbps 36.7 Mbps 11.9 Mbps
Apple iPad 3 (5GHz) 36.7 Mbps 36.7 Mbps 36.7 Mbps 11.7 Mbps

With a similar WiFi stack and similar antenna placement, it's no surprise that I noticed very similar WiFi performance to the iPad 2.

The same goes for GPS performance between the new iPad and the iPad 2. Both devices were able to lock and track me driving around in a car with comparable accuracy from what I could tell.

Airplay Support with the new Apple TV

When paired with a second or third generation Apple TV, the iPad supports wireless display mirroring or content streaming to the iPad via AirPlay. In other words, if you have an Apple TV hooked up to your HDTV, you can use your HDTV as a large, mirrored, secondary display for your iPad—wirelessly. The only requirement is that you have a 2nd or 3rd generation Apple TV and that it's on the same network as your iPad. With those requirements met, enabling AirPlay mirroring is simple—just bring up the iOS task switcher, swipe left to right until you see the brightness/playback controls and tap the AirPlay icon.

Mirroring gives you exactly what you'd expect—a complete mirror of everything you see on the local iPad screen. All sounds are also sent over and come out via your TV's speakers—the local speaker remains silent.

The frame rate isn't as high on the remote display, but there's virtually no impact to the performance of the iPad itself. There's noticeable latency of course since the display output is transcoded as a video, sent over WiFi to the Apple TV, decoded and displayed on your TV via HDMI. I measured the AirPlay latency at ms, which is reasonable for browsing the web but too high for any real-time games. If you want to use the iPad to drive your HDTV for gaming you'll need to buy the optional HDMI output dongle.

While AirPlay mirroring on the iPad works at 720p, if you're playing a 1080p movie on the new iPad and you have a 3rd generation Apple TV, the video is also displayed in 1080p rather than downscaled to 720p.

Video playback is an interesting use case for AirPlay and the iPad. If you don't have mirroring enabled, you can actually start playing a movie on the iPad, have it stream to your TV via the Apple TV, and go about using your iPad as if nothing else was happening. Most apps will allow you to stream video in the background without interrupting, however some games (e.g. GTA 3, Infinity Blade 2) and some apps (e.g. iMovie) will insist on streaming their UI to your Apple TV instead.

Although iOS and the iPad don't do a great job of promoting multi-user experiences, using AirPlay to push video to a TV wirelessly is an exception. If you frequently load your iPad up with movies you can use it to keep others entertained while you either get work done or just goof around on your iPad at the same time. It's a great fit for families where people want to do two different things. If you do put a lot of movies on your iPhone/iPad, the 3rd generation Apple TV is probably a must buy for this reason alone.

Gaming Conclusion & Controller Support: An Android Advantage What's Next: 6th gen iPhone, Haswell & Windows 8
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  • PeteH - Wednesday, March 28, 2012 - link

    No idea. Was it necessary to upgrade the GPU to get an equivalent experience on the larger screen in that case, or was performance on the 3GS limited by the CPU (or RAM, or something else)? Reply
  • zorxd - Thursday, March 29, 2012 - link

    just look at benchmarks on this web site

    The iPhone 3GS gets more FPS in 3D games because of the lower resolution.

    So in short, yes, it would have been necessary to upgrade the GPU to keep the same performance.

    But no matter what Apple does, people will always say it's the right choice.
    Reply
  • PeteH - Thursday, March 29, 2012 - link

    I looked for a comparison between 3GS and 4 game FPS comparison and couldn't find anything. Can you point me to it?

    I'm looking for hard numbers because just increasing the resolution doesn't necessarily mean a GPU upgrade is necessary. If (and this is completely hypothetical) the 3GS was performance limited because of its CPU, improving the CPU in the 4 could allow it to achieve the same performance at a higher resolution.

    I'm not remotely saying this is the case, just that I've seen no numbers demonstrating a drop in frame rate from the 3GS to the 4.
    Reply
  • dagamer34 - Friday, March 30, 2012 - link

    I believe the GPU got a clock speed increase when it went from the 3GS to the 4. Reply
  • Peter_St - Monday, April 2, 2012 - link

    Oh wait, let me rephrase this: I have this nice shiny tower with 2GB of RAM and newest CPU out there but shitty OS with java hogs and memory leaks, but who cares, I'll just go and jerk off on the specs.

    I think that's what you wanted to say...
    Reply
  • tipoo - Wednesday, March 28, 2012 - link

    GPUs which consume hundreds of times more watts than SoCs like this and have much more memory bandwidth at their disposal still struggle with the resolution this thing is displaying. The Xbox 360 GPU has, if I recall, around 25GB/s vs 6 in this, and that struggles to run games at 720p in a constant 30FPS. So far, it seems like the retina compatible games do display at native res, but there aren't any improvements in textures, effects, etc. So would the additional GPU power effectively be negated by the resolution for native apps, and still be constrained to games that look straight out of 2003-4? Or is Imagination Tech's video memory compression that much more advanced than AMDs/Nvidias so bandwidth doesn't matter as much? Reply
  • zorxd - Wednesday, March 28, 2012 - link

    It's not only about the resolution. You could probably play Doom just fine with the SGX543MP4 at this resolution. The problem is when you have more complex level of details, shaders, etc. The iPad couldn't play a game like Crysis even at half resolution. But even at 2048x1536, Doom will still look like a game of the 90s. Reply
  • tipoo - Wednesday, March 28, 2012 - link

    *12.8GB/s, my mistake Reply
  • BSMonitor - Wednesday, March 28, 2012 - link

    What's battery life watching a bunch of movies.. say from New York to Hawaii? Will I be able to get 9 hours??

    Can run all the compute benchies we want, but primarily these are portable entertainment devices. The simplest use being the most common.
    Reply
  • PeteH - Wednesday, March 28, 2012 - link

    Depends how bright you want the display, but from the number they're posting you should be fine at < 70% max brightness.

    I would argue that the most common use case is probably web browsing though, not movie watching. Unless... how often are you on these flights from New York to Hawaii?
    Reply

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