Definitely 900/160 - if it's stable at 40MHzPCI. All parts incl. PCI would be overclocked, and many programms require higher memory bandwidth first, and then faster CPU.
At 1GHz @118 you will either underclock the PCI bus (using 1/4 devider) running at 29.5MHz or overclock it to close to 40MHz, but your memory transfer is 25% lower.
Yo