P5B Deluxe - Mix SATA 1.5 and 3.0 drives?

[spiderhole]

I'm building my new system around the P5B dlx, and using a wd 320gb sata 3.0 as the Secondary drive. I want to use the Raptor 150gb as the primary/boot drive, but worried that using a sata 1.5 will slow down the sata 3.0 drive. Do you have to turn all sata ports to 1.5 mode in order to get a device of that type to work?

Thanks,
Mitch