Source: http://gizmodo.com/5943615/the-iphone-5s-a6-boasts-1gb-of-samsung-ram
During the iPhone 5 announcement, Apple mentioned the new phone would have its own new chip, the A6. Specific specs were sparse then, but AnandTech did some sleuthing and found the custom chip packs 1GB of RAM, and 33% more peak memory bandwidth than the iPhone 4S, which it will need for its high-res screen.
As it turns out, the alphanumeric code on the right side of the chip is actually a Samsung part number, and by digging through Samsung's product guide, AnandTech was able to find that the A6 has two 512MB DRAM die for a total of 1GB, and a speed of 1066 MHz. Basically, Apple's custom little chip here should be dishing out a performance boost.
The iPhone 5's peak memory bandwidth is 8528 MB/s, or a 33% improvement over the iPhone 4S's 6400 MB/s, and it's going to need it to push the pixels for the higher resolution display. That said, it's nowhere near the new iPad's 12800 MB/s, but then again, it doesn't need to be, considering it doesn't have such a mammoth screen to deal with.
Considering information gleaned from Xcode and Apple's insistence that we'll see better battery life on top twice the performance, the A6 literally doesn't fit into any sort of chip architecture we've seen before. It looks like Apple built this one more or less from scratch. There are, of course, other factors at play when it comes to how the iPhone 5 will perform on the whole, but we'll just have to wait and see about those. [AnandTech]