CPU CORE TESTING ON 1903

Most people are unaware what has changed with Windows 10 version 1903 and improperly assume only some cosmetic changes have been done.

The core kernel scheduler has been changed significantly. What used to be done to switch cores used to be around 30 microseconds has now been speeded up to 1-2 microseconds. Modern processors with 4 to 16 threads are able to handle more tasks in memory so the faster cycle time makes the operating system much more responsive.

The reason for the faster switching is driven by more and more cores in the typical processor as well as the slight unevenness between cores on a typical CPU. While a CPU is sold as being able to run at some marketed speed, for the most part it can achieve that within a tight margin.

The L2 and L3 cache on modern processors has increased considerably and this allows the operating system very fast capability to handle tasks as needed from main memory. The updated scheduler can take better advantage of modern hardware.

The redesigned scheduler will also benefit mobile users. The new design is intended to make the kernel as efficient as possible which notebook and tablet users will appreciate. Estimates vary but savings of about 5-7% on battery life have been noted.

r5-3600-taskman-cpu-cores

If the processor powering your rig supports “favored” cores, users will notice performance improvements as Microsoft has implemented a new rotation policy that will send more CPU intensive or critical tasks to those cores that operate faster. With Intel Turbo Boost Max Technology 3.0, lightly-threaded performance is optimized by identifying your processor’s fastest cores and directing your most critical workloads to them.

The scheduler is basically a ring buffer that has pointers to each running task. The kernel is able to work with one or more cores so the scheduler can load more tasks into memory and execution can be rotated using a timer.

NUMA

Windows is designed for a non uniform memory architecture so it can cope with different memory speeds and capacities. Corporate servers tend to have all identical machines with identical memory etc. Dual socket machines are not that expensive and many developers use them.

The new chiplet designs will likely show slightly more disparity between core logic when compared to a monolithic processor. A move to marking chiplet devices for thermal material application makes sense.

The chiplet design appears to be necessary due to the inability to get adequate yields for larger dies. The AMD Ryzen chiplet has an internal bus called the infinity fabric that syncs with main memory for best performance. Ryzen 3000 processors support DDR4-3200 which is enough bandwidth for PCI Express needs.

AMD has been offering more PCI Express lanes than Intel does with their budget lineup. This is why nVidia had to add a high speed bus for cards to communicate with each other to compensate. AMD has dual PCIe x8 slots for dual gaming cards with nothing other than power needed to run them.

GOLDBACH

The Goldbach tool uses OpenMP to saturate a processor no matter how many cores are present. Testing the R5 2400G it was found to run slightly above the marketed speed. The OEM CPU thermal material was replaced with Arctic MX-4 which helped the CPU remain cooler under load.

Goldbach is not hard to understand. For any even natural number 4 or greater, there are the sum of two prime numbers p and q, that equal it. Never proved, empirical testing to the limits of x64 show it holds. 4 = 2 + 2, 6 = 3 + 3, 8 = 5 + 3, 10 = 5 + 5, 12 = 5 + 7, 14 = 7 + 7, 16 = 5 + 11.

Goldbach also makes the case for the short word problem. The eventual move to 128-bit registers helps but 256-bit make more sense generally. Memory is currently 64-bit wide and it can be widened to 256-bit easily. With fiscal policies, inflation will push CPU word sizes soon.

Testing the machine with the fuzzy donut showed the graphics is struggling at 3840×2160 which comes as no big surprise.

So considering the CPU and benchmarking, anything in Windows will not be the same as with earlier versions of Windows which use an early task manager. So for that reason it’s wise to be cynical when vendors offer this or that over their rivals.