The Steam listing for F1 2015 now offers system specifications for F1 2015, showing the racing game sequel requires a 64-bit OS and 4 GB of RAM (thanks DSOGaming). Here goes:

MINIMUM:
OS: Windows 7 64 bit or Windows 8 64 bit
Processor: Intel Core 2 Quad @ 3.0GHz or AMD Phenom II X4 @ 3.2GHz
Memory: 4 GB RAM
Graphics: Intel 4th Gen Iris Graphics or AMD HD5770 or NVIDIA GTS450
DirectX: Version 11
Network: Broadband Internet connection
Hard Drive: 20 GB available space
Sound Card: DirectX Compatible soundcard
Additional Notes: Supported Graphics Cards: DirectX 11 Graphics Card Required Intel: 4th Gen Iris or Higher, Intel Iris Pro Series AMD: HD5770 or Higher, HD6770 or Higher, HD7750 or Higher, R7 250 or Higher, R9 Series Nvidia: GTS450 or Higher, GT545 or Higher, GT640 or Higher, GT740 or Higher, GTX900 Series

RECOMMENDED:
OS: Windows 7 64 bit or Windows 8 64 bit
Processor: Intel Core i7 4770 or AMD FX 9370
Memory: 8 GB RAM
Graphics: Intel 5th Gen Iris Pro or AMD R9 290 or Nvidia GTX970
DirectX: Version 11
Network: Broadband Internet connection
Hard Drive: 20 GB available space
Sound Card: Direct X compatible soundcard
Additional Notes: Intel, the Intel logo and Iris are trademarks of Intel Corporation in the U.S. and/or other countries.