You cannot find Build 40 on pirate sites or random file hosts safely. The only legitimate, virus-free method is via (or GOG). The developers, The Indie Stone, wisely allow players to roll back to any previous version via Steam’s "Betas" feature.
It runs smoothly on "toaster" PCs that lack a dedicated graphics card. project zomboid build 40 download
Downloading an older version of a game like Project Zomboid can be a bit tricky, but here's how you can do it: You cannot find Build 40 on pirate sites