The additional transistor budget also allows Carrizo to become the first processor in the industry designed to be compliant with the HSA 1.0 specification developed by the HSA Foundation. HSA makes programming accelerators such as the GPU far simpler, ideally leading to greater application performance at low power consumption.
Chief among the design advantages for HSA is the heterogeneous Unified Memory Access (hUMA) within Carrizo. With hUMA, the CPU and GPU share the same memory address space. Both can access all the platform’s memory and allocate data to any location in the system’s memory space. This coherent-memory architecture greatly reduces the number of instructions required to complete many tasks, thus helping improve both performance and energy efficiency.
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New Energy Efficient Features
Several new power-efficient technologies make their debut on the Carrizo APU. To deal with transient drops in voltage, which is known as droop, traditional microprocessor designs supply excess voltage on the order of ten to fifteen percent to ensure the processor always has appropriate voltage. But over-voltage is costly in terms of energy because it wastes power at a rate that is proportional to the square of the voltage increase. (i.e. 10% over-voltage means about 20% wasted power).
