Acer 5920G Graphic card replacing

I got this Acer Aspire 5920G with a faulty HD3470 256MB. I tried to fix it with a heatgun and it worked but later I tried to flash the BIOS for doing an underclock and it failed. Now I got a bricked card. I want to replace it with a new HD3650 from Ebay ( New ATI Mobility Radeon HD 3650 MXM II 256MB DDR3 Graphics VGA video Card Acer | eBay). It says that have a ACER VBIOS, but I don't know if it will work on my notebook. What do you think?

Sorry about my English, I write from Spain.

 

It should work just fine.
For other cards that are confirmed to work see here.

 

Finally I bought a HD3470 256MB DDR2. It's the same that I had before, I want to be sure that it works. I read on that post few messages from people that were having troubles with the HD3650.

 

I have one more question. What I should use on GPU? Thermal pad or thermal paste?

 

First of all - don't use pads. If there is a need for something more than just a thermal paste, use a copper shim. If not - got for paste only.
Thermal pads are not that great in terms of thermal conductivity.

 

And what I do with the thermal pads on the memory chips? I change it for thermal paste or I live it?

 

Thermal pads are OK for memory chips - memory doesn't get even nearly as hot as the core so it's not that essential to cool it down.
We are talking about DDR2 here - it would do without a radiator at all if it had to.

 

I asked because I read on forums that there is a lot of space between the GPU and the heatsink and some people said that was having troubles using only thermal paste.
I read that some people used cooper pads instead of thermal paste or thermal pads. There is enough space to use only thermal paste on GPU?

 

I can't tell you that - you should see yourself if the radiator makes good contact or not.If it doesn't than copper shim is the way to go.

 

The new card arrived yesterdat. I installed it and worked, now I get these temps on idle after 3 hours powered on. Are they safe?

 

Safe- yes. Particularly good - no.

65*C at idle is slightly too hot. Check what happens under load- if it doesn't heat up too much you can as well leave it as it is.
If it gets above 85/90*C (which BTW is not an unsafe temperature) it probably means you need to tweak the setup a bit (possibly with a copper shim).