Processor
The processor has changed the least. It's a 65nm Merom-based Core 2 Duo with a few tweaks, and will be the last of these CPUs before the arrival of 45nm Penryn processors in the next update. The major change between Santa Rosa's processor and its predecessors is the acceleration of the frontside bus (FSB) from 667MHz to 800MHz , together with the ability to slow it down during light loads. This technology, called Super Low Frequency Mode, knocks the bus speed down to 400MHz, the CPU's clock speed to 600MHz and reduces the core voltage. Another tweak, called Enhanced Deeper Sleep, means that the memory controller in the chipset won't wake up the processor to check on cache status if the system knows the cache is empty and the CPU is sufficiently comatose not to be able to change things.
A rather unusual performance boost comes in the form of Enhanced Dynamic Acceleration Technology. The Santa Rosa processor can run one of its two cores at full tilt while the other is in one of a number of sleep states, at which time the total thermal energy is somewhat less than the maximum allowed when both cores are running. Under conditions where only one core is running, Intel can effectively overclock it, taking advantage of the increased thermal headroom left by the other core ticking over. This will give single-threaded tasks a boost, says Intel, without risking overheating.
