physical RAM restriction in Fedora 12 (32 bit and 64 bit)

[Mark Ryden]

Hello,
  AFAIK, in windows 7, **32 bit**, there is a limit of 3GB physical
RAM which can be recognized by the operating system.
This means that if you have 4GB of RAM, only 3 will be used.
My question is:
1) In Fedora 12 32 bit default installation , does the kernel knows
more than 3 GB of RAM ? what is the limit ?
2) In Fedora 12 64 bit default installation , does the kernel knows
more than 3 GB of RAM ? what is the limit ?

Rgs,
Mark