Windows 10 Performance Variability and Intel Thread Director
However, Intel pointed out that you'll get the best performance with Windows 11 and that you can expect some performance variability if you use Windows 10. That means performance can be inconsistent, with programs running faster sometimes and slower at other times.
With a mix of both performance and efficiency cores, Intel's biggest challenge lies in assuring that the correct type of workloads land on the correct cores. It's easy to see that having a core that excels at high-performance workloads isn't much help if the high-performance workloads consistently land in the slower cores. Unfortunately, thread scheduling systems based entirely on static rules (priority, foreground, background) tend to be inefficient and create software programming overhead.
Intel's Thread Director technology is the key here. This hardware-based technology uses a trained AI model to identify different types of workloads at the chip level. It then provides that enhanced telemetry data to Windows 11 via a Performance Monitoring Unit (PMU) built into the chip. The operating system then uses that data to help assure that threads are scheduled to either the P- or E-cores in an optimized and intelligent manner.
However, while Windows 11 exploits Thread Director's full feature set, Windows 10 does not. Due to optimizations for Intel's Lakefield chips, Windows 10 is aware of hybrid topologies, meaning it knows the difference between the performance and efficiency of the different core types. Still, it doesn't have access to the thread-specific telemetry provided by Intel's hardware-based solution.
As a result, threads can and will land on the incorrect cores under some circumstances, which Intel says will result in run-to-run variability in benchmarks. It will also impact the chips during normal use, too. Intel says the difference amounts to a few percentage points of performance and that the chips still provide an "awesome" user experience. We'll have to see how that works in the real world to assess the impact.
Intel also says that users can assign the priority of background tasks through the standard Windows settings, but these global settings apply to all programs. So it remains to be seen if that will have a meaningful impact on performance variability in Windows 10.
Alder Lake Performance
According to Intel's claims, the hybrid architecture pays big dividends when it functions to its fullest. We already covered many of the performance and efficiency highlights in our Alder Lake deep dive, but Intel also shared a few important new nuggets.
Intel says that the E-Cores provide the same level of single-threaded performance as Intel's Skylake architecture used in the Comet Lake chips, which is phenomenal even though Intel conducted this test at a fixed frequency (you might not get that level of single-threaded performance in normal use). Remember, four of these small cores fit into the same space as one Skylake core.
Intel also claims an impressive generational leap in power efficiency, with the Alder Lake-S chip running at 241W being 50% faster than the Core i9-11900K at 250W. More impressive, Intel claims that the 12900K can deliver the same level of threaded horsepower at a mere 65W as the 11900K gives at 250W, representing a massive performance-per-watt advantage.
Intel also shared a few other new details about how its Thread Director assists Windows 11, but we'll save most of that deep-dive info for the review.