| ARMv7 | ARMv8 |
| 15 general purpose registers | 31 general purpose registers 64-bits wide. |
| 16 FP/NEON registers 64-bit wide | 32 FP/NEON registers 128-bit wide |
Other difference:
hardware acceleration of AES and SHA1/SHA256 algorithms.
new advanced SIMD instructions.
Double precision SIMD FP math is now supported among other things.
記憶體上限我覺得不是很大的重點
資料來源：http://www.anandtech.com/show/7335/the-iphone-5s-review/4
