How to overclock a ati mobility radeon HD 4650

OK so what temperature is OK when overclocking and will it give a performance boost?thanks for the help

how do i know if the overclock setting is stable and i can play games on that setting

I have an ATI Mobility Radeon 4600 with a 440.00 Mhz. GPU and memory speed of 560.00 Mhz. (DDR2,I think) and a Core 2 Duo CPU at 2.56 Ghz and 4GB RAM, in a Toshiba Satellite A505 notebook.

I am thinking of trying it,using ATI Tray Tools.It can auto overclock,while scanning for artifacts.It can do it for GPU and Memory.The WEI score for gaming graphics is 6.7 and after running the ATT benchmark a few times,it came up with a score between the high 5000's and low 7000,with the final one coming it at 6099.51 (with Firefox running).On the final run's compare chart,it was topped by:

3rd:X1800XT (AMDX2 2.5Ghz) (600Mhz GPU/702Mhz Mem)
Score:6716.52

2nd:X1900XT (AMD64 2.8Ghz) (625 GPUMhz/725Mhz Mem)
Score:7516.78

1st:X1900XTX (P4 3.9Ghz) (648Mhz GPU/774Mhz Mem)
Score:8212.08

My question is,is it worth trying it and risking damaging my 2200 dollar Satellite? One would think the auto overclocking would not take it so far it would be a big problem,but I am afraid it will.Second of all,it may already be plenty good enough to not bother with.I can run Skyrim on Ultra High quality setting without much problems (same can be done on games like Quake 4 and Doom 3,even though they are a little older now).