Here is the arp list and here are the MACs on bridge most time the arp list have 100-300 entries only. so does the bridge.show the output of
ip arp
An 1100ah2 will handle this easily: Just logged onto one of ours, has 1135 active connections on a 100MB fibre, CPU is at 39%
This box often has 1800+ users, cpu maybe around the 50% mark.