Intel Skylake eDRAM, P States And Imaging Engine
There are new security technologies dubbed Intel Software Guard Extensions (Intel SGX) onboard Skylake, which support new instructions and flows to create and isolate enclaves from malware and privileged software attacks. And then there's Memory Protection Extensions (Intel MPX) to help protect stack and heap buffer boundaries as well.
The cache structure itself hasn’t changed much in Skylake, but throughput has been increased in multiple areas. LLC mishandling and fabric throughput has been doubled, and eDRAM can now be used as a Memory Side Cache. The eDRAM is fully coherent now, can cache any data, and is available for use by the core, I/O, and display engine. There is also no need to flush the eDRAM for coherency maintenance.
Although Skylake is manufactured using the same 14nm process as Broadwell, it offers better power consumption characteristics completely through architectural enhancements. The power requirements for every interconnect have been improved, total SoC power efficiency is improved with many multimedia workloads, and idle power is better as well.
A new technology, dubbed Intel Speed Shift, also allows Skylake to switch P states (power states) much faster than previous-gen products. Skylake can control P states fully in hardware, whereas previous-gen products required OS control. The end result is that Skylake can switch P state in 1ms, whereas it takes roughly 30ms with older processors. Speed Shift, however, requires changes at the OS level for proper support.
Further improving power efficiency are additional Speed Step domains. Speed Step in Skylake supports gating of the System Agent, DDR and eDRAM I/O. Skylake has an integrated camera ISP as well.
There has also been a number of updated made to the graphics engine in Skylake—we’ve detailed those in a separate article, available here. Overclocking in Skylake is more flexible than the last few generations of Core-branded processors too. We talk about overclocking in our review of the Core i7-6700K.