Ram, how does it help games when the video card has it too?

how does ram help my video cards performance?

VRAM is more or less only a buffer between your PC and your monitor.  It stores each image before it's displayed.  It also stores data used directly in video computations.  Textures, etc. It's optimized differently, and specifically for the purpose of storing images.  You can share them, but it will either be slower (using all system RAM) or more expensive (using all VRAM)  

System RAM helps performance mainly in the manipulation of data that the CPU needs, and game load times.  All files get loaded onto system RAM first, if I remember correctly, so it is a bottleneck.  Most games don't have a very high system RAM requirement.  

cpu & gpus compile and compute data- the more computations that can be done in a given time is frame rate.

Where do the cpus & gpus get the data to compute and execute? the harddrive? NO! wayyyyy too slow. It's in the RAM.

by nature Vram is faster than regular cpu ram because gpus are more powerful and need the speed so they're not slowed down.

Lets say you're playing BF3 and for it uses 1.5GB of Vram. Lets say you have a card with 1GB of Vram. well what happens? as your gpu is processing the data to render your video it's calling on different parts of the ram to get the data and execute it. But some of that data (.5GB) is not there. It's stored somewhere else further away. This means the gpu now has to go get it from where it is and then it has to wait for the data to come back. thus slowing the whole process down. 

On the flip side let's say you have 2GB of Vram and the game takes up 1.5GB. It's like filling up a tank. I does no harm if you don't fill it up all the way, it just means it's unused and not slowing anything down.

also- if you're gaming @ a higher resolution, that game will most likely take up more ram. EG 1080p vs 1440p

Does this make sense?

 

I like this explanation :p

makes sense