[ixp1200] ix bus throughput limitations

[liam noonan]

Hi,

I have carried out some testing  on a single thread process receiving 
and counting packets (code from chapter 5 from ixp 1200 book)
When it runs at wire speed at 177Mhz and Ixbus at 66 Mhz it has a 
receive rate of 350 Mbps at the IX bus.
The same rate is achieved when running at 200Mhz, Ixbus at 66Mhz. I 
would expect the receive rate to be faster.

Does anyone have any idea as to why the receive rate isn't higher for 
200MHZ?

Thanks
Liam Noonan
Univeristy Of Limerick