I was running 3.1.3 on my iphone 3G, jailbroken and running well.

I decided to upgrade to IOS.4.0.1.
After upgrading, I jailbroke.

Since being on IOS4.0.1 it was terrible... so slow!

I decided to clear and restore all settings and restore the phone to an unjailbroken state.

So now I have IOS4.0.1 (unjailbroken) and it is still running terrible. I have deselected some settings like 'searchlight' to try to speed it up but it is very poor.

I will give it a little bit of time and then will probably look into restoring v3.1.3
I understand the 3GS works with IOS4.0.1 without any problems but I would not recommend upgrading to this version for the 3G model.

Anyone experiencing the same thing as me?