Intel Core i5 12600K / Core i9 12900K "Alder Lake" Linux Performance

Written by Michael Larabel in Processors on 4 November 2021. Page 1 of 14. 126 Comments

With the Intel 12th Gen Core processors shipping today along with the new line-up of Z690 motherboards, the review embargo lifts for talking about these Intel "Alder Lake" processors. While by now you've likely heard a lot about Intel Alder Lake on Windows and various leaked benchmarks with Windows 11, how does these processors with the new hybrid architecture work and perform on Linux? Here are the initial benchmarks and support information for Intel's Core i5 12600K and Core i9 12900K processors under Ubuntu Linux.

This is the first of many Linux articles to come on Phoronix looking at Intel Alder Lake performance. There are several follow-up articles already in the works for the days ahead and then over the weeks ahead will be benchmarks across many Linux distributions, Linux vs. Windows 11 performance figures, and more. Today's article is going to be short and to the point with only having received the Alder Lake samples at the end of last week. So due to that short turnaround time to embargo lift, testing has been tight but thanks to the Phoronix Test Suite automation still have many results to share today and basic compatibility metrics.

Intel kindly provided the Core i5 12600K and Core i9 12900K review samples to Phoronix for testing. Additionally, they also provided 2 x 32GB Corsair DDR5-4400 memory and the ASUS ROG STRIX Z690-E GAMING WiFi motherboard with those components used for all of this Alder Lake Linux testing.

Intel's Hybrid Architecture With P + E Cores On Linux

The most pressing matter when it comes to Alder Lake on Linux is the new hybrid architecture with the mix of performance (P) and energy efficiency (E) cores... To date Intel has not posted any Linux kernel patches for providing any software optimizations around this hybrid architecture and the new Intel Thread Director. Hopefully they will soon but already it is too late for seeing in Linux 5.16.

But how does Alder Lake perform with currently released kernels? At a high level, it's fine. For some workloads it was clear when they were pegging the E cores when instead should have been to P cores (as shown when getting to the benchmarks in this article). Those eager enough could always use features provided systemd / cgroups to ensure a given application runs on particular core(s), but in terms of the intelligent handling between P and E cores, there is more work to be done for Linux.

For most demanding workloads, the P cores were being called into action while some moderately intense workloads were still ending up on the E cores. This was found for Linux gaming especially with lower than expected results but for those engaging in heavy Linux workloads on desktop CPUs, the i5-12600K and i9-12900K overall were working out better than anticipated given the lack of any Thread Director patches.

Intel UHD Graphics 770 On Linux

One of the other immediate issues Linux users may face with Alder Lake is if planning to use the integrated Intel UHD Graphics 770. While Intel has been bringing up Alder Lake graphics for a while as covered in many Phoronix articles over the past year, up through the recently released Linux 5.15 kernel the Alder Lake graphics are not enabled by default.

Thus when initially booting these new processors on recent Linux distributions like Ubuntu 21.10 or even going with Linux 5.15 mainline, the system will fallback to software acceleration. My testing was with Linux 5.15 and when using the i915.force_probe=4680 option, the Alder Lake graphics were working fine. If using a recent kernel you should likely be in good shape with using that force probing workaround, but too bad Intel wasn't more punctual in readying the support by default.

The Gen12-based Intel UHD Graphics 770 were working out well on Linux 5.15 + Mesa 22.0-devel (Mesa 21.3 should also be in good shape). A separate article will cover the UHD Graphics 770 performance more extensively. The only instability issues were to be found in a few Vulkan compute tests but for gaming with OpenGL and Vulkan was woring out fine.

Z690 Motherboards & Linux

All of my Alder Lake testing so far has been using the ASUS ROG STRIX Z690-E GAMING WiFi motherboard given that's all I currently have available. Using this motherboard under Ubuntu 21.10 has been working out fine. With Linux 5.15 the main issue is a long shutdown process, but may be resolved with updated firmware/BIOS. I have heard from others though having Linux boot issues and other quirky behavior with Linux and different motherboards, but will likely all be resolved as well with new firmware/BIOS releases. We'll see in the weeks ahead if any new Z690 motherboard issues remain under Linux, but at least for this ASUS motherboard tested it has been working out reliably.

Linux CPUFreq Frequency Reporting

All of our Alder Lake benchmarking and of other processors were carried out at stock speeds. At least with the platform we are using, the frequency reporting under Linux is borked. Linux seems to think the Core i5 12600K can clock up to 6.3GHz and the Core i9 12900K up to 6.5GHz... Obviously not accurate. That information is also thus conveyed on our automatically-generated system information tables.

With those Linux support notices out of the way, let's get to looking at some Linux performance numbers.

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