Memory Bandwidth
DVMT (Dynamic Video Memory Technology) systems share system memory, which causes increased bus traffic to/from the GMCH (graphics and memory controller hub) and system memory. Therefore, faster memory = real-world performance gains.

PC100 = single data rate memory at 100MHz
• Bandwidth = 64bit x 100MHz / (8bits/byte) = 800MB/sec
  
  PC133 = single data rate memory at 133MHz
• Bandwidth = 64bit x 133MHz / (8bits/byte) = 1064MB/sec
  
  DDR200 = double data rate memory at 200MHz (100MHz x 2)
• Bandwidth = 64bit x 200MHz / (8bits/byte) / (1024MB/GB) = 1.6GB/sec
  
  DDR266 = double data rate memory at 266MHz (133MHz x 2)
• Bandwidth = 64bit x 233MHz / (8bits/byte) / (1024MB/GB) = 2.01GB/sec
  
  DDR333 = double data rate memory at 333MHz (166MHz x 2)
• Bandwidth = 64bit x 333MHz / (8bits/byte) / (1024MB/GB) = 2.60GB/sec
  
  Dual Channel DDR400= double data rate memory at 400MHz (200MHz x 2)
• Bandwidth = 64bit x 400MHz x 2 channels / (8bits/byte) / (1024MB/GB) = 6.25GB/sec

• Cost
  Less total system memory required to perform a wide range of operations - why pay for 32MB of video memory that sits idle and unused?
• Efficiency
  Textures and other items are already in main system memory and do not have to be transferred over the AGP bus, increasing efficiency of memory usage and less AGP bus traffic

• Intel® 82915G graphics controller
• Intel® 82865 graphics controller
• Intel® 82852/82855 graphics controller
• Intel® 82845 graphics controller
• Intel® 82830 graphics controller

This applies to:

Intel® 82810 Graphics and Memory Controller Hub (GMCH) Intel® 82815 Graphics Controller Intel® 82830M Graphics and Memory Controller Hub (GMCH) Intel® 82845G Graphics Controller Intel® 82852/82855 Graphics Controller Family Intel® 82865G Graphics and Memory Controller Hub (GMCH) Intel® 82915G/82910GL Express Chipset Family Mobile Intel® 915GM/GMS, 910GML Express Chipset Family