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Samsung to Produce Faster Graphics Memory
Samsung has announced a new line of GDDR5 chips that will supposedly be able to deliver data at speeds of up to 6 Gbps. In addition to faster data delivery the new chips also claim to consume less energy than previous versions. "Samsung said the new chips consume 1.5 volts, making them about 20 percent more efficient than GDDR 3 chips. Samples of the GDDR 5 chips began shipping to graphics-processor makers last month, and Samsung plans to begin mass production of the chips during the first half of next year. GDDR 5 memory should first appear in high-end gaming systems where users are willing to pay a premium for better graphics. Samsung did not disclose pricing for the chips.
The difference is we are talking about semiconductor devices. Losses from these semiconductor devices are primarily due to leakage and switching. As long as we're still using silicon, leakage will be roughly 0.5 V^2/R, no matter how much current you pump through the transistors. Switching losses occur in when logic changes from 1's to 0's due to the capacitance of the transistors. The power lost here is roughly 0.5 f C V^2, where f is the switching frequency and C is the capacitance (material dependent). The V^2's means that reducing the voltage has a significant impact on losses. If we note that R and C are completely determined by the material (silicon) and the fabrication process, we can see that as long as the frequency is held constant, the voltage is a reasonable metric for comparing power consumption in silicon devices.
Of course this analysis is purely approximate since there are a lot of there things going in the devices. And I'm assuming complete capacitive discharge (independent of switching frequency), and didn't consider the changes in refresh rate to this DRAM device. But suffice it to say voltage is still a pretty good metric for comparison (until you actually build the thing and test it).