We just installed the Adobe Creative Suite CS6 at work and I'm surprised to find Fireworks so incredibly unresponsive to the point it is unusable. I opened up a small layout I had been working on (only a handful of objects and layers) and there is a delay of about 5 seconds between selecting and object and being able to move it or interact with it in any way.
I am a longtime Fireworks user and find this completely unsatisfactory. I will have to go and fetch CS5 and reinstall.
What gives Adobe?
8 GB RAM
Boy, that sounds weird—as in, it sounds like something's gone wrong beyond the anticipated.
I recently upgraded from FW8 to CS5 (a big jump) and then to CS6. I left all versions installed. CS5 and CS6 work comparably. No major complaints—with performance, anyway. Granted, I'm using Snow Leopard (OS 10.6.8) but have just 4 GB RAM. Fireworks CS6 is the version that's supposed to be optimized for Lion, so you should have the best results with that pairing (compared to CS5).
I'm no tech support expert. I'd be a little nervous about installing CS5 on top of CS6. But only because it might mess with CS6 components. I've heard you're best off installing later versions on top of older versions. (I imagine that could be fixed with another CS6 install, if needed.)