That really just depends. It is DDR 400 RAM, but it is also suppose to be pretty good overclocking RAM. It would just depend on how far your CPU is able to go and how far your RAM is able to go before you would know whether it would be beneficial to use a divider.
The 146 runs at 2Ghz right? Anyways, let's suppose it does. Stock settings are:
RAM 200Mhz 1:1
Let's say your CPU is able to do 2.6Ghz max AND that RAM is max stable at 260, or DDR520. You would simply set it at:
RAM: 260Mhz 1:1
Now lets say your CPU can still max at 2.6Ghz, but the RAM max's at 240. The you might go with something like:
CPU: 290x9 = ~2.6Ghz
RAM: 240 with a 6:5 divider