c4d on leopard

i was looking for a thread on this issue but couldn't find one so i apologize if this is redundant. i'm sure many other people are having this problem. after installing Leopard, using c4d (10.5 in my case) completely bogs down my system. moving in viewports takes forever, as soon as you get even the slightest bit complex, as well as non-c4d things like opening a finder window or surfing the web. it feels like your computer is frozen during the rendering of each frame, and the only time you get control of anything is the brief period of time between the rendering of each frame. you certainly can't do any photoshop or after effects work while rendering in c4d on leopard. i've read forums on cineversity and some say it requires an apple update, some say a maxon fix but they all seem to point to the advanced renderer as the problem. now, i have the core version of 10.5. not XL and not studio. the modules i have are mograph and unlimited net rendering. to my understanding, advanced renderer is a separate module that doesn't come with the core version, which would suggest that i don't have advanced renderer, but i'm still having the problem of the program consuming my computer's resources. it also crashes any net rendering i do...it often crashes the net render server (which renders the clients useless), but when it doesn't crash the net render server, it bogs down any computer that has a net render client on it.

i'm sure other people are experiencing this. can you confirm that you are? are people (apple and/or maxon) working to fix this?

if anyone has more information on this and when to expect progress to fix the problem and from whom, i would greatly appreciate it.

thanks

(i work on a dual 2.7 G5, 4gb ram, OS 10.5.1, cinema 4D r10.5)