A few months ago, you asked your interlocutors on this site to give them an example of a configuration for a graphics workstation; What I'm interested in.
Also, if you would like to tell me for about 1000€ off-screen a list of equipment in line with these parameters below, I thank you in advance.
So there you have it, for Toshop and for LR4 (or higher version), indeed, it is not necessary to have a CAD workstation. The cost of such a station would exceed your budget anyway (1600€)
I recommend this machine which will bring you appreciable working comfort.
I'm saying that, I'm not saying anything but for a graphic designer's machine, if I remember correctly, the configs under OSX (mac) are very much appreciated.
Today, although not approved by Apple (but nevertheless not uneven), it is possible to build a configuration worthy of a Mac Pro (or almost) with a rather weak bugdet.
If you're interested, just buy an OSX license and go to a few sites whose addresses I'll provide without any worries if interested, and select the components accordingly.
End of the Hs, good luck!
Edit: here are 2 links to illustrate my words, they are testimonials from pros who have taken the plunge: