Power Consumption & Thermal Testing With The Core i9 7900X On Linux

Written by Michael Larabel in Processors on 29 June 2017 at 10:50 AM EDT. Page 1 of 6. 19 Comments.

Following my initial Intel Core i9 7900X Linux benchmarks this week were questions raised about its power use and thermal efficiency. Here are some tests looking at those factors, including the performance-per-Watt.

As a refresher, the Core i9 7900X Skylake-X has ten cores plus Hyper Threading for a total of 20 threads, supports quad-channel DDR4-2666, clocks in at 3.3GHz with a 4.3GHz turbo frequency and 4.5GHz TBM3 frequency, and 13.75MB cache. This $999 USD chip offers a lot, but in exchange has a 140 Watt TDP. For perspective, the Ryzen 7 1800X has a 95 Watt TDP and the Core i7 7700K has a 91 Watt TDP.

My testing so far has been with air cooling and it has worked out using an Arctic Cooling Freezer i11 and Noctua NH-D9L heatsinks for testing.

I ran some comparison tests on a Core i7 7700K (also using an Arctic Freezer i11) and then some power consumption numbers for the AMD Ryzen 7 1800X too. No thermal numbers for the Ryzen 7 though since the latest Linux kernel still doesn't have support for the thermal sensors of Zen/Ryzen. Both the Core i7 7700K and Core i9 7900X were running within Rosewill 4U cases.

The Freezer i11 has long been my go-to heatsink for Intel CPUs within 4U cases due to its ~$20 price and great performance and fits easily in a 4U case while is rated for up to 150 Watts, but given the intensity of the i9-7900X, I had also purchased a Noctua NH-D9L.

The Noctua NH-D9L is a dual-tower CPU cooler and measures in at only 110mm tall, which could allow it to even fit in a 3U chassis.

The thermal/power tests on these three systems were done using Ubuntu 17.04 x86_64 with the Linux 4.12 kernel and Mesa 17.2-dev. The systems all had 16GB DDR4-3000 memory, Samsung 950 PRO NVMe 256GB SSD, and Radeon RX 480 graphics card.

Core i7 7700K vs. Ryzen 7 1800X vs. Core i9 7900X Linux Power + Thermal

The AC system power consumption was monitored using a WattsUp Pro power meter that in turn interfaces with the Phoronix Test Suite for automatic polling during the automated benchmarking process.

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