is it possible to upgrade the ATI 5850M graphic card with GDDR3 VRAM to another one like a 5850M with 1GB GDDR5 or I will geht problems with the temperature?
Short answer: no. Sorry!
Long answer: While it may be physically possible to replace your GDDR3 GPU with the GDDR5 version, there are a number of things going against you:
* Good luck finding one to buy (I'm pretty sure these are only sold in bulk as OE to notebook manufacturers).
* You will need to do extensive surgery on the laptop and have good soldering skills. Laptop video cards are not meant to be upgraded/replaced.
* You will have to edit BIOS to accept the new data rate.
* It will void the warranty of your laptop.