I tried starting up a new world of Minecraft today, and found much to my displeasure that something as simple as breaking a tree, on a single-player world, would run into glitchy, laggy, unplayable problems.
My computer is...rather old. It has a AMD Athlon II 620 Quad-Core processor, a Nvidia 9100 integrated graphics card, 4 G of Ram, 640 GB hard drive, and it runs Windows 7. I literally updated java just yesterday, so...what am I missing to make Minecraft run properly?