原鏈：http://www.computershopper.com/feature/the-right-gpu-for-you7
Where graphics cards typically have anywhere from 128MB to 768MB of their own onboard graphics memory, motherboard-based integrated graphics solutions use your PC's main memory, sharing the RAM your processor uses to hold programs and data. Most motherboards allow you to choose how much memory you want to set aside. Typically, the range is 64MB to 256MB, and some can change this value on the fly as necessary. Intel's G965 chipset, for instance, uses Dynamic Video Memory Technology (DVMT) to allocate memory for graphics as needed.
Whatever memory is allocated to the graphics chip is memory you can't use for programs and data. With 256MB set aside for graphics, your 1GB system is suddenly functionally equivalent to a 768MB system. Depending on which applications you use, that can bog down your system by requiring it to swap data out to disk more often.
Of course, you can add more memory to offset this. A 2GB system won't notice a missing 256MB chunk of memory nearly as much as a 1GB setup will. Another option for memory-challenged Vista systems is a ReadyBoost-compatible USB thumb drive, which you can use to augment internal system RAM.
