Yeah, my best guess is that you'll be able to run it at a decent frame rate on a mixture of settings. I'd expect them to have lots of ways to fine tune it.
I'll be trying to get a new pc in time for it, something that'll also be stronger than next-gen consoles. I like to have a bit of leeway to make up for poor optimisation, though I'm expecting CP to be very well optimised.
Not sure about 8 GB of RAM. I have the same amount in my rig and I sometimes run low on memory when I'm playing huge open-world games like Forza Horizon 4. Like me, you might have to shut down any applications and useless background tasks to have the most amount of memory available.