A large amount (more than a third) of DRAM power can be due to page activation (see http://download.micron.com/pdf/technotes/ddr2/TN4704.pdf and http://www.micron.com/systemcalc). Assume you are building a system with 2 GB of memory using either 8-bank 2 Gb 8 DDR2 DRAMs or 8-bank 1 Gb 8 DRAMs, both with the same speed grade. Both use a page size of 1 KB, and the last-level cache line size is 64 bytes. Assume that DRAMs that are not active are in precharged standby and dissipate negligible power. Assume that the time to transition from standby to active is not significant.

a. Which type of DRAM would be expected to provide the higher system performance? Explain why.

b. How does a 2 GB DIMM made of 1 Gb 8 DDR2 DRAMs compare with a DIMM with similar capacity made of 1 Gb 4 DDR2 DRAMs in terms of power?