Commodore's VIC-20 was the successor to the PET. It was a hit due to its very low cost ($300, versus $1500+ for the IBM PC introduced that same year), and had a pretty decent library of arcade ports. Its TV ad starring William Shatner is still remembered as the watershed moment when home computers were first positioned as worthy and cost-effective rivals to dedicated game consoles. However, the VIC-20 was also a weak hardware, with low-resolution graphics and very little RAM, meaning it was only adequate for games and edutainment, not productivity applications. As its limitations became too apparent to ignore, Commodore released the far superior and more successful Commodore 64.