Using the New iMacs with Native Drives

I’m thinking about buying a new iMac coming out in a few days. The base 21.5" model comes with a 5400 rpm internal drive though. So will that work ok if I just have the OS (Mountain Lion) and Cubase on that drive, but the VSTs, samples and recorded audio going to a 7200 rpm external drive. Will there be problems with Cubase itself on the slower drive?