Replacing iPhone battery increase performance?

[arcrius]

My girlfriend's iPhone is laggy, a restore didn't do anything. Would replacing the battery help?

 

[Applejuiced]

No.

 

[arcrius]

you know of any ways I could?

 

[Applejuiced]

you know of any ways I could?

What kind of iphone in question is slow?
My guess would be an iphone 3G correct?
Usually a restore and setup as new will fix most lag but if you're on a 3G and higher than 3.1.3 it will drag either way.
I would suggest to update to a 3GS or iphone 4. You wont be able to make it go any faster cause the hardware is not there to handle the latest iOS well.