They all were really demanding (as for the versions, there have been quite a few. I know I played a DOS/95 based one back in elementary school.). For 2004 to max it, you probably need something along the lines of a Pentium 4 3GHz or so and a G80/R600 based GPU (or an upper end G71/R520), which is pretty high for 2004. For sure it is single threaded, so count that as easy.