Disable multi-tasking on 3g?

[mikeyp6]

Hello,

I own an iPhone 3g on firmware 4.0, and jailbroken using redsn0w (95% sure I used redsn0w) I enabled multi-tasking during the jailbreak, but I would like to disable it now, as the phone has become frustratingly slow, and apps crash constantly. What is the easiest way to disable multi tasking and/or improve performance?

[iYeow]

Install Disable multitask from Cydia, trigger it from Winterboard.

[mikeyp6]

Thank'd