What command I can use to check my graphics card's memory? I have an on-board Intel Graphics card, and I am unsure if it's memory is 128 MB or 256 MB!
If it is an Intel integrated GPU, then it would be using a unified memory model where there is no dedicated graphics memory, and instead main memory is used. More information can be found on Wikipedia
So the answer is either 0MB or however much main memory you have in the machine, depending on your point of view.
With the modern drivers, the actual amount of memory used by the GPU will vary with the work load: there isn't a fixed amount set aside for the card.
Note: since this question was asked, Intel has released a GPU with its own memory: the Iris Pro Graphics 5200, which has some DRAM embedded on the chip. All other GPUs still rely on main memory.