Earning Points. Starwood's Preferred Guest program is fairly straightforward: the more nights you spend at participating hotels, the faster you'll earn a free night.
As seen in the EXECUTING phase, the map will write (using Mapper.Context.write()) its output into a circular in-memory buffer (MapTask.MapOutputBuffer). The size of this buffer is fixed and determined by the configuration parameter mapreduce.task.io.sort.mb (default: 100MB).
Bottom line: 2GB for dual monitor, 4GB for more than 2 monitors. Find the best GPU chipset from benchmark test sites. To answer what is the role of memory, it is where all your vertex (geometry), terrain, mesh , texture data of your game is stored and GPU does computations on that. If there isn't enough space in GPU memory modern GPUs are capable of juggling data between VRAM (a dedicated memory portion of CPU RAM) and GPU RAM.