[Nemo]

You can get the most bang for your buck by getting the most powerful CAD specific graphics card in your price range and a healthy amount of RAM. Spending extra on the processor will probably provide less performance per dollar.

This summer I put together a computer specifically to work on Inventor models at home and have been very happy with it. I was looking for good value, and this is the meat of what I ended up buying:

ATI FirePro V4800 ($160)
AMD Phenom II x4 965 3.4 GHz ($130)
BIOSTAR A870U3 motherboard ($65)
8 Gb RAM (G Skill model F3-10666CL9D-8GBRL) ($55)

I have been very pleased with the build. It has no problems with robot assemblies with hundreds of parts, and its frame rate is really nice with smaller stuff. It is also at least decent while running the most complex assemblies I've created or the ones you can download courtesy of teams 148/228/973/etc. It doesn't run those larger assemblies at a sick frame rate or anything, but I'm also not waiting around for it to zoom or rotate (or restart from a crash) like I was on my old computer.

The processor could have been any number of other chips - I picked this one because I liked the performance vs price. I thought about spending twice as much on a Core i5, but now I'm glad I didn't. It is important to note that Inventor makes very little use of multiple processors, although I suppose that could change in future versions. And I like having spreadsheets and browsers open while I play with Inventor.

When you research video cards for Inventor, you will quickly identify the ATI FirePro line and the nVidia Quadro line. There is a price jump from $160 to $400 in each company's product line, ignoring older models. Both of the $160 cards can handle my most complex models pretty nicely.

If you are interested in a pre-built computer, you will want to be careful. You will pay a little extra for the convenience of having HP build it, of course. A bunch of workstation builds have weirdly chosen components, with unimpressive graphics card on the low end and pointlessly expensive processors on the high end. Our school just bought a handful of HP workstations with Core i5 processors, 4 GB RAM, and Quadro 600, and that particular workstation is about the most balanced build I can find if you want a decent amount of power for under $1000. I opened up a complicated robot assembly on one of them, and it ran nicely. I don't know the model number of that workstation, but you can search it up for something like $700-800. HP doesn't sell any low-mid models with 8 gigs of ram, but you can get the extra 4 GB for $30 if desired.

Happy shopping!