The difference between 4GB or 8GB on a low spec laptop?

[Collinsaurus]

I recently went from 4GB to 8GB on my laptop. The general specs are Quad core 1.5Ghz cpu, was 4 GB of RAM now 8GB, 500 Gb HDD. I use this laptop mostly as a work laptop for corresponding with clients and minor Photoshop. ( I am a GFX artist and I don't use this laptop to make GFX. I will often make edits to text ETC ). 4GB was plenty for doing that however I occasionally play League of Legends. I could barely pull 30 fps and I assume that was because my cpu technically doesn't meet requirements. However I had an laptop from brother because he won a contest and got a new one. I pulled the 4gb ram stick from his and put it in mine. They are both Kingston 4gb sticks and both have the same Mhz however I do not remember it. But I can now run League of Legends at 60 FPS at the same graphic settings. How is this possible? From what I read an extra 4GB shouldn't make a very big difference?

 

[Tradesman1]

It can make a big difference, 4GB on a laptop is actually very little as the OS will take up up DRAM and the laptop will assign a fair amount to to iGPU, and will often share even if the laptop has a dedicated GPU with it's own VDRAM. With 8GB the game actually has DRAM to really use

 

[InvalidError]

If you are even the slightest bit short on available real memory to run software, the OS will start relying on the HDD (swapfile) to make up the rest and as soon as the HDD gets involved, performance goes down the drain regardless of how fast everything else in the computer might be. Having 8GB drastically reduces the frequency and severity of those events.