Is window xp Better for dell N5110 than window 7?

Well, Windows XP is now fairly old, and it doesn't support DX11 or 10 like Windows 7 does. Win7 is kind of a RAM hogger than WinXP ( but much better than Vista..).
Dell however, does recommend Win7. Older software/games would run on WinXP but you can run them on Win7 too with Virtual XP (not present in all of the Win7 versions, however).

I don think so. He is just asking for his specification. Hey man... answer is Yes, Do instal Windows 7 but better 32 bit cuz of your i3. if you have a 2nd gen i3 processor then.Have this windows 7 64 bit provided you have 3 or 4 gb of ram.. Okay... dats the answer

Don't know what you are trying to say, but the OP just asked which would be better, XP or win7.
If the OP does use some older softwares, it's best if he keeps to WinXP. And if he's short on RAM, WinXP can prove itself as being useful..

win7 64bit