TI84+ better than a TI89 Ti ??

Hello people,

I'm a high school student currently doing AP Calculs. Uptill now i was using a TI86 to solve problems, most people in my class use a TI84+, and i noticed that my calculator was pretty slow compared to theirs.

For Example, integrating the expression: cos(sqrt(x)+x),x,0,60 (in radian mode) use to take almost 2 min to calculate (ans is -1.19075).

Nyways, the point is, now i use a TI89 Titanium, which is faster than the TI86 in the sense that it takes about a min to solve the above expression. Wat suprisses me is that a TI84+ only takes 10 seconds!(Headbang)

Does anyone know why is it like this or is their a problem with my calculator? also i dont hav a lot many apps and stuff installed. Can the battery be the problem?

Thaks in advance.

PS: It would be great if somebody using a TI89 could solve the above expression and see how long it takes...