Open-E support 32bit and 64bit both Single and SMP , you can change the booting kernel with command line utility , please take into consideration that replication doesn't work between 32 and 64 bit you need to be either full 32bit or full 64bit , about memory I would like that Open-E give some info about this because during my test I could not get better performance with memory over 2GB ( I tested up to 5GB )