I want to run heavy games. is there any big difference of graphics between intel and nvidia. or nvidia just increase the speed of games? and what is its worth.?
you cannot replace your gpu, the intel is on die ( on the cpu) most higher end laptops have dedicated gpus from either nvidia or amd and those in most cases cannot be replaced or upgraded either since they are soldered in place.
there are kits you can buy if your laptop has a spare mini express port which you can buy a kit to run a dedicated desktop gpu
you cannot replace your gpu, the intel is on die ( on the cpu) most higher end laptops have dedicated gpus from either nvidia or amd and those in most cases cannot be replaced or upgraded either since they are soldered in place.
there are kits you can buy if your laptop has a spare mini express port which you can buy a kit to run a dedicated desktop gpu
Your laptop cannot be upgraded with a graphics card, sorry to say. That saying, HD4200 is not too bad, and you can probably play a number of games on low settings.