[cesarb]

The L1 size is yet another place where the x86 legacy hinders things. To avoid aliasing in a virtually indexed L1 cache (which is what you want for performance in a L1 cache, since a physically indexed cache would have to wait for the TLB lookup), the size of each way is limited to the page size, which on x86 is 4096 bytes. To get a 64 KiB L1 cache, it would have to be a 16-way cache, and increasing that too much makes the cache slower and more power-hungry. It's no wonder Apple decided to use a 16 KiB page size instead of a 4 KiB page size; a 64 KiB VIPT L1 cache with 16 KiB page size needs only 4 ways.

For the L1 instruction cache, aliasing shouldn't be a problem (since it's never written to), but this is once again another place where the x86 legacy hinders things: instead of requiring an explicit instruction to invalidate a virtual address in the instruction cache, it's implicitly invalidated when writing to that address.