I’m happy that I was wrong in my prediction about the first round of apps crashing due to memory issues. At least for the most part.

Although it seems that many developers had their apps rejected because they did not work very well when tested on real device, compared to running in the simulator. I think a large portion of these issues can be attributed to memory, or lack thereof.

It is now confirmed that the iPad only has the same amount of memory as the iPhone 3GS: 256 MB. Why couldn’t Apple spend a few dollars extra on a $500 device to double the memory to 512 MB? I think one answer can be found in iFixit’s teardown of the A4 processor. The memory is actually built-in to the same package as the A4 CPU. This makes for blazing fast access to the memory by the CPU, which is important when moving around large blocks of memory quickly for displaying on the screen. Having the memory chips physically close to the CPU also reduces the power consumption significantly. But cramming in the memory chips into the CPU “chip” limits the amount of memory you can have. It’s not like you can just add a standard SIMM module with more memory.

All hardware design is an exercise in trade-offs. For the iPad Apple had to find the best trade-off between:

• Memory capacity
• Memory access speed
• Battery life

In their infinite wisdom, Apple settled on 256 MB of RAM for the first iPads. And we developers have to learn how to live within those constraints.

Post from iPhone Development Blog Copyright © 2009 Nick Dalton - iPhone Developer

Why does the iPad only have 256 MB of RAM?