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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  • sjael - Wednesday, March 28, 2012 - link

    On the 'A5X vs Tegra 3 In the Real World' page, you mention Modern Warfare 3 as a iOS+Android game.

    I think, since I haven't seen this game ported to phones/tablets, you *might* be thinking Modern Combat 3.

    And then of course you show the market page for it further down..
    Reply
  • Anand Lal Shimpi - Wednesday, March 28, 2012 - link

    Correct - thanks for the heads up!

    Take care,
    Anand
    Reply
  • Celestion - Wednesday, March 28, 2012 - link

    Looks like the 3rd gen iPad was CPU limited in that first GlBenchmark test. Reply
  • Anand Lal Shimpi - Wednesday, March 28, 2012 - link

    That would be vsync :)

    Take care,
    Anand
    Reply
  • Celestion - Saturday, March 31, 2012 - link

    I see. Thanks! Reply
  • Kevin G - Wednesday, March 28, 2012 - link

    Memory bandwidth tests just seem to be off for what you'd expect a quad channel 128 bit wide memory bus to perform as. Performance didn't move from the dual channel 64 bit wide bus in the iPad 2. Could there be a software bug (Geekbench or iOS) limiting performance there? It'd be nice to revisit the memory tests after the next major revision of iOS and in conjunction with a later release of Geek Bench.

    Any chance of getting the exact resolution that Infinity Blade 2 runs on the rev 3 iPad? I'm assuming it'd be either 1536 x 1152 or 1368 x 1024 for quick scaling purposes.
    Reply
  • slashbinslashbash - Wednesday, March 28, 2012 - link

    They addressed this in the article.

    "It would appear that only the GPU has access to all four channels." - Page 12

    The GPU is hooked up to the RAM controllers. The CPU communicates to the RAM through the GPU. The GPU gets all 4 channels, the CPU only gets 2. The benchmark measures CPU-RAM bandwidth, not GPU-RAM bandwidth.

    It's actually kind of interesting, as it's an inversion of the typical architecture that we're all used to from PCs. But it makes sense, since the new iPad is basically a very nice screen with a smartphone CPU attached. The very nice screen requires a very nice GPU to drive it, so the GPU is more important (and would be memory starved with only 64 bits). The CPU just has to be "good enough" while any shortcomings in the GPU would be magnified at this resolution.
    Reply
  • tipoo - Wednesday, March 28, 2012 - link

    Which way is the PS Vita configured? That has the same quad core GPU and a quad core CPU as well. Reply
  • tipoo - Wednesday, March 28, 2012 - link

    Huh, the Vita actually has 128mb dedicated video memory, can't find the bandwidth though. Reply
  • pickica - Monday, April 02, 2012 - link

    We should also consider a possible higher clock on Vita. Reply

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