He's right.
Look, right now a ship in game consists of an unique ID number, a mesh, 3 textures(color, normal and data), a position, a vector and speed.
Add in just one turret, and you have an additional ID number, mesh, 3 more textures, a position, a vector, and another speed.
Now lets make it a Kol with about 15 weapons. You make that one ship take almost 16 times the processing power to keep track of.
As it is in Beta 4, I've seen my 3ghz Dual core start to choke up when I had myself and 3 AIs all at max fleet cap on a very large map. It helps that 3 of us had almost all our junk in the same system at the same time, in some kind of battle to the death. (I lost, they teamed up on me

) It wasn't my GPU, I checked my performance logs and it was definitely the CPU with both pegged at 100% for about 5 minutes.