Apple iPad 2 Preview
by Anand Lal Shimpi, Brian Klug & Vivek Gowri on March 12, 2011 6:01 AM ESTWiFi + 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.
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erple2 - Tuesday, March 15, 2011 - link
In the iOS case - they're synonymous. You can't get the "new" browser without also getting the new OS update.tipoo - Saturday, March 12, 2011 - link
In addition to software differences, each company also tweaks the design of the Cortex A9 to their liking. After ARM licences it out they can do pretty much whatever to it. So you might see Qualcomm adding cache, Nvidia doubling the bus, or whatever.metafor - Tuesday, March 15, 2011 - link
ARM core licenses do not allow you to modify the CPU design. ARM allows different options when configuring cache size and bus width and co-processors but only with their macro-generator. There's definitely flexibility, but it's not "whatever you want". There are limited flavors if you will of yummy goodness.Anand Lal Shimpi - Saturday, March 12, 2011 - link
While the underlying architecture between those devices may be similar, there are some differences. For example NVIDIA's Tegra 2 only has a single channel 32-bit LPDDR2 memory interface while TI's OMAP 4 has a dual-channel LPDDR2 memory interface.Tegra 2 also lacks an MPE (SIMD engine) while the OMAP 4 doesn't.
Take care,
Anand
tipoo - Saturday, March 12, 2011 - link
I'd be interested in a comparison between all these mobile processors. I understand its difficult since the iPad uses a different OS, but given the numbers where do you think it stands compared to Tegra 2 and the like?zhill - Saturday, March 12, 2011 - link
My understanding is that the ARM Cortex A9 is just an instruction set and architecture specification/chip design. Each company manufactures the actual chips themselves so they can make additional changes at the hardware level such as lithography, voltage, clock frequency, cache sizes etc. So they license the design from ARM, but build the silicon themselves so each design may vary in terms of actual implementation and performance.Software also certainly makes a difference.
winterspan - Saturday, March 12, 2011 - link
you are right to an extent. There are actually two different licenses, a manufacturing license and a "design" license. Basically, if you pay more for the design license, they can make a custom core that implements the ARM Cortex v7 instruction set. This is what Qualcomm does with their Snapdragon. Most of the other guys just have the manufacturing license and this enables mild adjustments, but essentially they all have to use a similar Cortex-A9 core.Not sure what the Apple cores are... Standard Cortex-A9 or something more custom from Intrinsity/Samsung?
jmmx - Sunday, March 13, 2011 - link
"If Apple iPAD 2, NVIDIA's Tegra 2, TI's OMAP 4 and Samsung's Exynos all use the same Dual Core ARM Cortex A9…"There is more to it than this. The simple fact is they do NOT "use the same Cortex A9." They each user their own implementation of the A9. Additionally, A9 is the core cpu design, but the chips are SoC chips "System on a Chip" That is, they contain a lot more than just the A9 CPU but other non CPU functional units as well.The configuration of these units can significantly affect performance.
This is my understanding of the situation. (Caveat - I am a software engineer not hardware.) Someone out there feel free to correct me if I am mistaken about this.
str1ke007 - Saturday, March 12, 2011 - link
Can the ipad2 be tetherd to an iphone ?? (so i can use the 3G data i allready pay for rather then paying for another sim/plan)kmmatney - Saturday, March 12, 2011 - link
There is no reason why you couldn't, and this is what I plan on doing. However I would like to know if the map and GPS apps work well on an iPad without 3G. Do you need to get a 3G for the GPS to work properly?