In terms of game file size, you will need at least 4 GB of free disk space available. QB Sim system requirements state that you will need at least 8 GB of RAM. An Intel Core i5-4590 CPU is required at a minimum to run QB Sim. Whereas, an Intel Core i7-7700 is recommended in order to run it. The cheapest graphics card you can play it on is an NVIDIA GeForce GTX 1060. Futhermore, an NVIDIA GeForce GTX 1070 is recommended in order to run QB Sim with the highest settings.
QB Sim will run on PC system with W7 and upwards.