i dont use 3d Max..
But i do some 3d dwg using Inventor, and alot of 2d and 3d using autocad.
My workstation:
CPU: i5-4570
GPU: nvidia Quadro K600
Ram: 16gb
No lagging when doing 3d. Of course it based on how big is your file.
Starting up is slooowwwww..
So you need SSD for your installation of 3d Max programe..
for your budget.. have a go at zreo_chaos bro recommendation..
but i suggest u get at least 8gb first.. if not enough, slap another 8gb..
and get that gtx 750 TI, intergrated graphic intel 4600 is CMI.. if budget not enough.. search for 2nd hand
and if you getting inwin 644 casing, check if the graphic card can fit.