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RXi2-BP Hardware Reference Manual
GFK-3187B
Section 8:
Thermal design with modern x86 processor architecture is a complex topic with many variables that
contribute to the final performance:
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8.1
x86 Processor Thermal Design Features
8.1.1
Dynamic CPU Frequency and Boost Modes
Modern x86 architectures made a significant improvement in increasing computing performance while
reducing power and heat dissipation at the same time. In a typical application, CPU activity varies and
highly depends on memory, storage, and other I/O devices. When CPU needs data for the
computation, it attempts to process it as quickly as possible and then, while waiting for the next set of
data, goes to a low frequency, low power mode. Following this strategy, modern CPUs can transition to
a very high CPU frequency (high power), but only for a limited time, and will then need to slow down
and wait for more data. Such bursts of CPU activity come at a relatively high rate
(milliseconds/microseconds). This strategy allows an increase in observable performance, while
simultaneously averaging out to a lower heat dissipation. RXi2-BP and the AMD Ryzen processor that it
uses supports these techniques, and they are enabled in UEFI settings by default. It is highly
recommended to keep these settings enabled so that performance and thermal advantages of the
architecture can be utilized.
8.1.2
CPU Throttling
One other important aspect of modern x86 architecture is the CPU's ability to protect itself from
thermal events. This is called CPU throttling and results in the CPU reducing it's operating frequency
when it reaches its maximum temperature. This throttling effect occurs automatically, and at the first
glance might not be obvious to the user. Application performance, however, will be significantly
reduced in this case and might lead to a variation in performance test results. To avoid performance
loss due to CPU throttling, it is recommended to ensure that the CPU temperature is significantly lower
than its maximum value in the worst-case ambient air environment. RXi2-BP is designed specifically to
optimize heat transfer from the CPU die to the external heatsink, and in most cases will not be a factor
in limiting Industrial PC performance.
Thermal Performance
Thermal Performance
CPU Maximum frequency (user configurable)
CPU Boost mode (Turbo mode) (user configurable)
Software application and the worst-case workload it creates for the CPU
Peripherals being used (display, USB devices, number of active Ethernet ports)
IPC mounting, orientation, clearances
Ambient air temperature and how static the air is (airflow)
Section 8
November 2020
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