The Fastcoin P2Pool network has been able to sustain well over 500 MH/s.
http://www.inetrader.com:5150/static/ has been able to withstand the abuse of these heavy hitting, high hashrate miners. With properly configured hardware, it is possible to mine Fastcoin on the P2Pool quite effectively regardless of your hashrate.
It is suggested that
large hashrate miners can fine tune their hardware to reduce DOA. Reducing intensity is another way to ensure you're mining efficiently.
Example: adding /16 to the end of your payout address, as well as lowering the intensity on your hardware.