Make sure you’re RAM is sitting clean.. meaning installed correctly. Depending on your configuration, RAM still needs to be installed in pairs; even on the quad/Xeon machines.
Check that first. Maybe it’s not fully in or mixed out-of-pairs.
Change your resolution to the next lower setting and see if that does anything. That would be a test for the vid card. Better yet, crank it down to 800 x 600 and take it for a spin.
I’m only on C4d 8.5 but I also run CS3 apps, including After Effects and I don’t have an issue and this is on a G5 iMac (non-Intel)