Intel debuted multiple new papers and low-power advances at ISSCC this year, including a GPU core far more efficient than any the manufacturer has previously produced.
The International Solid-State Circuits Conference (ISSCC) is this week, and it’s a time when companies and researchers meet to discuss cutting-edge advances in semiconductor technology. Intel is giving several presentations at the conference this year, with new details on the future of low-power computing and some previously unknown information about Haswell CPUs.
When Intel launched a version of Haswell with 40 GPU execution units and 128MB on-package EDRAM, codenamed Crystal Well, it played coy with many of the details. Die size, clock speed, and organizational structure were all swept under the rug — until now. We now know that the Crystal Well EDRAM is a separate (but on-package) 77-square-millimeter chip clocked at 1.6GHz with a 1V operating voltage. The interface between the CPU/GPU and Crystal Well is called the OPIO (on Package I/O) and it’s a simple, flexible design that Intel has deployed in two forms. On Haswell-ULT (ultra-low power) chips, the OPIO link is a 4GB/sec bridge between the on-die Platform Controller Hub and the rest of the core. When deployed alongside Crystal Well, the OPIO can transfer 102GB/s — at a nominal cost of just 1W of power.
Other disclosures the company made confirmed some of our speculation from a year ago. When Intel announced that Haswell would have an on-die voltage regulator, we speculated that the FIVR (Full Integrated Voltage Regulator) was a step Intel took in order to speed its transition time from idle to full load and back again. 0W has become the new 1GHz — the faster a chip can move in and out of idle, the more horsepower it can bring to bear on specific tasks and the more power it can save in the transitions.
As Anandtech reports, our speculation on this front appears to have been correct. FIVR is highly efficient (90% under load) and can enter/exit sleep in 320 nanoseconds and clock to full Turbo in just 100 nanoseconds.