DOOM - Closed Alpha PC Requirements:

Minimum Spec (720p)
  64-bit Windows 7/Windows 8.1
  Intel Core i5 @ 3.3 GHz or better / AMD FX-8350 @ 4.0 GHz or better
  8 GB RAM
  NVIDIA GeForce GTX 660 (2GB VRAM) / AMD Radeon HD 7870 (2GB VRAM)
  6GB HDD space
  Steam account
  High speed internet connection

Recommended Spec (1080p)
  64-bit Windows 7/Windows 8.1
  Intel Core i7 @ 3.4GHz or better / AMD FX-8350 @ 4.0GHz or better
  8GB RAM
  NVIDIA GeForce GTX 780 (3GB or more VRAM) / AMD Radeon R9 280 (3GB or more VRAM)
  6GB HDD space
  Steam account
  High speed internet connection