Nope not really...The more things you install though the more it lags
...I've jailbroken every firmware there has been since i got mine and they all lag
And if you install A LOT! of things it will even freeze up, and then you just have to restore again. But right now with just cydia mine isn't real laggy at all
If it gets too bad just re-jailbreak it...Takes like 10 minutes