Vostro 1510 Hot GPU temp

I have dell vostro 1510 with following configuration
C2D T5670 1.8GHZ
4GB RAM
256MB DDR2 8400m gs

I just got my fan replaced. Fan is working fine now and cpu is lot cooler but GPU is running way hotter(reaching 100c on load). Earlier it never used to go beyond 85-86 on stress test.
But guy told me that he had just replaced fan and applied new thermal pad on GPU and new thermal paste on processor. He opened laptop in front of me and showed both of them placed perfectly. He also reassembled carefully and heatsink is perfectly fit.

So why am I getting a hot GPU?

Is thermal pad of poor quality?

Should I apply thermal paste(have heard that usually there is gap between heatsink and GPU and that's why thermal pad is applied to cover gap)

Can I use combination of thermal pad and thermal paste?

Also recommend me thermal paste and thermal pad if you recommend to replace

 

Perhaps the pads are just too short to reach the heatsink, cause they usually have a depth. Before changing the thermal pad it should use the correct height, or this maybe stupid he forgot to take off the adhesive pad to protect it from drying?

If you going to use thermal paste you need copper shims.... better to have the old thermal pad to get the correct height.

But if you still got the old thermal pad in good nick, you can put them back on to see if that is better.

 

I don't have old thermal pad. He told me that old thermal pad was torn when he took it out. New thermal pad is thick enough and it is tight enough.
Is there any chance that sensor might have gone bad? When I run furmark gpu stress test it goes upto 106c but heatsink still feels warm not too hot.
Also stress test continues to run perfectly, no hangs, no shutdowns

I mean if I don't look at temp then there is no way to suggest that GPU is so hot

 

I haven't heard of the diode temperature being faulty just like that.... right after a fan change (coincidence?), as they are located within the chip itself. I would say that he perhaps didn't clean the GPU surface properly, as the thermal pad isn't transferring the heat correctly. Some thermal pads has oil like materials to prevent drying. If your temperature are obviously differ to the previous I would just change the thermal pads, cause 100oC is too hot and most likely damage your GPU which are non-replaceable for a Vostro.... meaning you have to get a new motherboard.

p.s. Also remember reading that the Nvidia has thousands of the 8400m GPU faulty with heat thermal flaws, which I would advise to keep it low...very low unless you going to get another system anyway

 

Do you know any place from where I can get thermal pads?
I am also thinking about changing laptop as everyone says that 8400 and 8600 are ticking time bombs

 

I normally buy my thermal paste on the internet, I use copper shim. So I cannot say what thermal pads are best, but you should get them replaced ASAP. As you may have a dead GPU. As I know someone with the same Nvidia chip, cause quite alot of hassle with an non-functional system.