Here are the official system requirements for D3 upon release in less than two months!

Test your system specs now before it’s too late and runs into your pwning time for Diablo 3!

MINIMUM SYSTEM REQUIREMENTS FOR DIABLO 3 

Windows

Windows® XP/Vista/7 (latest service packs) with DX 9.0c
Intel Pentium® D 2.8 GHz or AMD Athlon™ 64 X2 4400+
NVIDIA® GeForce® 7800 GT or ATI Radeon™ X1950 Pro or better
1 GB RAM (XP), 1.5 GB (Vista/7)
12 GB available HD space
DVD-ROM (required for retail disc versions only)
Broadband** Internet connection
1024×748 minimum resolution

MAC

Mac® OS X 10.6.8, 10.7.x or newer
Intel® Core 2 Duo
NVIDIA® GeForce® 8600M GT or ATI Radeon™ HD 2600 or better
2 GB RAM
12 GB available HD space
DVD-ROM (required for retail disc versions only)
Broadband** Internet connection
1024×768 minimum resolution

RECOMMENDED SYSTEM REQUIREMENTS FOR DIABLO 3

Windows® Vista/7 (latest service packs)
Intel® Core 2 Duo 2.4 GHz or AMD Athlon™ 64 X2 5600+ 2.8 GHz
2 GB RAM
NVIDIA® GeForce® 260 or ATI Radeon™ HD 4870 or better

Mac® OS X 10.7.x or newer
Intel® Core 2 Duo
2 GigBytez RAM
NVIDIA® GeForcez® GT 330M or ATI Radeon™ HD 4670 or better