You might be able to find Rhino performance stats by weeding through the Holobench scores here on the forum.
I can’t see why you would have problems with an Alienware, unless you count carrying it. I have an older Quadro K2100M in my Lenovo W540 laptop, and a GTX 1080 in my 2700k desktop. Obviously, textured triangles don’t care about class; my GTX 1080 will run rings around my laptop chip–irrespective of the marketing with the graphic chip.
Some of the older AMD drivers seemed to have transparency issues, but that was then.
[ My next desktop processor, will likely be an AMD]
A fast processor is nice. Sometimes, the i7s and laptop Xeon run faster because they have a larger cache; sometimes the lesser processors pretty so close that it’s not worth the extra money for the higher chips. Sometimes it’s better setting for the 2nd best processor, so you can upgrade your computer more often. I usually make speed/price graphs and buy just before the curve goes straight up.
Cinebench is a fairly good test for doing Design/Cad. Good single-core performance helps when you aren’t rendering; good multi-threaded performance helps when you are.
If you have a lot of objects, having a good graphics chip does help–until the system becomes processor-bound.
Rhino V6 has a GPU enabled rendering preview.
You should get enough memory to make sure that whatever you are working on does not push the operating system into using virtual memory. You likely want enough memory stick so your computer runs dual or quad channel, but you may not want a bunch of small sticks of memory that you have to have to try to sell on ebay first–if you want to install more.
I have virtual memory shut off on both of my computers because Windows uses it quite foolishly. Still, memory goes pretty far in Rhino.
CPU’s patched for Meltdown are coming. DRAM prices are starting to fall. GPU’s for the desktop are becoming less insane for price.