Every board I know of will default PC2700 memory to a CPU:RAM ratio of 5:4 in that configuration. Which means your CPU bus (800 bus has a 200MHz clock and Quad Data Rate) will run faster than your memory bus (160MHz clock, DDR320 rather than 333) and cause a performance loss. But yet it will work, which is your main concern. And in fact it will likely still outperform a 3.06.
<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>