Scheduled to be officially unveiled on 03 March 2012, the official demo for one of the most anticipated game of this year "Mass Effect 3" is now available for downloading on PC, XBOX 360 and PS3 platforms. The DEMO features two spectacular levels from the single-player campaign, along with intense four player co-op multiplayer matches.

Gameplay in Mass Effect 3 will be influenced by decisions from Mass Effect and Mass Effect 2 and have settings throughout the galaxy, including Earth and Mars. Combat has been changed and refined; in particular, the cover system has been improved, there will be more options for moving around the battlefield, instant melee kills and more conventional grenades will be introduced as well as improved artificial intelligence. A four player multiplayer co-op mode will also be available.

(via : Wikipedia)

Minimum PC requirements for Mass Effect 3 :

OS - Windows XP SP3/Vista SP1, Win 7

*Supported chipsets: NVIDIA 7900 or better; ATI X1800 or better. Please note that NVIDIA GeForce 9300, 8500, 8400, and 8300 are below minimum system requirements, as are AMD/ATI Radeon HD3200, HD3300, and HD4350. Updates to your video and sound card drivers may be required.

CPU - 1.8 GHz Intel Core 2 Duo (equivalent AMD CPU)

RAM - 1GB for XP / 2GB RAM for Vista/Win 7

Disc Drive - 1x speed

Hard Drive - 2.5 GB of free space

Video - 256 MB* (with Pixel Shader 3.0 support)

Sound - DirectX 9.0c compatible

DirectX - DirectX 9.0c August 2009 (included)

The recommended PC specifications are these:

OS - Windows XP SP3/Vista SP1, Win 7

CPU - 2.4 GHz Intel Core 2 Duo (equivalent AMD CPU)

RAM - 2GB for XP / 4GB RAM for Vista/Win 7

Disc Drive - 1x speed

Hard Drive - 2.5 GB of free space

Video - AMD/ATI Radeon HD 4850 512 MB or greater, NVidia GeForce 9800 GT 512 MB or greater

Sound - DirectX 9.0c compatible