[BBLISA] RAM for cluster net boot?

[Scott Ehrlich]

I'm looking at building a small cluster of disk-less 1 or 2U servers and will 
probably use CentOS 5.

Since these machines will not have any hard drives, what would be the minimum 
amount of RAM I'd need?   Also, if using Rocks or something similar, will that 
help cluster the RAM together so 4 servers x 4 GB RAM each = 16 GB available?

Some applications might be CPU intensive, others might be RAM intensive, so I 
need to play that balance, too.

Thanks.

Scott