32bit-PAE vs. 64bit

Hardware Hub CPU
1

I have a PC with 16GB of RAM, on this machine Iam running Ubuntu 32bit (latest alpha, 13.04 or something like that). So Iam wondering if I should change to a 64bit kernel instead, or does this have any effect at all on performance, or would it be better to change to a Physical Address Extended kernel. Is there a difference between the two, if so what?

Also running top, htop or free shows me that I have those 15G that I want, but maybe thats not a true value?

2

13.04 is still in alpha? It's due next month. I'd go 64bit; you'll get a performance increase, if anything and it should native support for up to 192GB of RAM.