replaced cpu with Core-I5 on low end laptop and now randomly shuts down

[menelaospc]

hello everyone,
i have been using these forums for a few years now and i need to say you guys have been doing amazing work.I never had to ask anything as i always found the information i was searching for.
Now i'm facing a challenge which is very wierd to me as everything looks good except the issue.
my girlfriend has a low-end hp 650 laptop with stock celeron cpu installed.
2 days ago the laptop was overheating so i thought i'd open it up to clean it and apply new thermal compounds.
I had an I5-2430m cpu lying around so i thought i'd also install the cpu.
now the laptop boots up just fine with idle temps around 32c and full load temps(using prime95) maximum at 65C(which i think are good)
problem is laptop randmly shuts down even when in idle.
sometimes it takes a few minutes, other times it works for a couple of hours.
while it's working its performing very good and i don't notice anything wrong.
the only thing i can think of is that there's some incompatibility but the Bios recognises the processor as it should.
any help would be really appreciated.
thank you

 

[Swapnil kum]

Looks like i5 is consuming more power than the celeron in idle. The laptop would be having a psu of low wattage.

 

[menelaospc]

i have also used the psu that came with the laptop i took the I5 from which is 19V 4.74A
and left it inside BIOS setup where it shuted down approx after 1 hour