SQL: AFFINITY MASK option

Hi all! We have a 4 CPU machine with a far to hight amount of Context Switches/sec (10.000 to 25.000). What I would like to do is, to set the AFFINITY MASK from bitmask 0000 (standard) to 1111 (15) … … but the SQL documentation says, that this is an option for SMP-Systems with more than 4 CPU! So, what would happen if I use this option? Maybe I can use it? Any other solution (can not use NT Fibres due to WinAuthentication of NAS)? Thanks in advance! Regards,