What is the best configuration for gaming xw6400

The specs I see show that computer as having 1gb system ram(2x512mb). You'd want 4gb(2x2gb) to run any modern version of Windows. That system uses DDR2 ram.

You'd need a power supply good enough to power the videocard you buy. If that computer still has the original power supply then you should replace it. It's a pre-built computer though, so it may use a non standard design, you should check that first.

Your Xeon CPU is a dual core, so you'd be limited to dual core friendly games, not PUBG or GTA V. In theory you could upgrade it to a quad core Xeon but I think that's probably A)not worth it and B)outside your abilities at this time.

Put something like an AMD HD 7750 in there and I think you could run some less demanding games, like some esports games. League of Legends, CSGO, and others like that.
 


i have already 4 gb ram and 1 gb nvidia 210