Tag Archives: Radeon

AMD Posts Linux Patches In Preparing For DisplayPort 2.0 Radeon GPU Support


The latest feature display work to happen for the AMDGPU kernel driver since the debut of FreeSync HDMI in Linux 5.13 is around DisplayPort 2.0 support and specifically the SST UHBR10 handling.

UHBR10 is one of the new data rates / modes of DisplayPort 2.0. With Ultra High Bit Rate (UHBR) 10 there is 10 Gbps per lane to allow 40 Gbps of bandwidth over passive copper cabling. The SST aspect of this patch series is just denoting it’s for single stream transport rather than multi-stream transport (MST).

DisplayPort 2.0 additionally supports UHBR 13.5 and UHBR 20 modes but this patch series for the AMDGPU direct rendering manager driver is just in regards to the UHBR 10 mode. UHBR is compliant with VESA’s DisplayPort 8K (DP8K) certification. Over DP HBR3, the UHBR 10 mode also allows for 4K @ 144Hz for standard video content and much broader support for HDR content at 4K and above at higher refresh rates than HBR3.

These six patches get the DP 2.0 SST UHBR10 support going after adding some five thousand lines of new code.

DisplayPort 2.0 was announced back in 2019 with a 3x increase to the data bandwidth performance, new power conservation features, and more. So far though the GPU hardware and driver support has been slow to materialize. Similarly, DisplayPort 2.0 monitors have been slow to reach market — reportedly delayed by the pandemic but could begin appearing in the months ahead.

Due to the timing of these patches, however, it’s not likely that they will get queued up for Linux 5.15 but more than likely divert to Linux 5.16. That though should ultimately be fine considering the latest-generation Radeon RX 6000 series supports DisplayPort 1.4. This AMDGPU DC work around DP 2.0 UHBR10 is likely in preparation for next-gen graphics (RDNA3 / Radeon RX 7000 series).

Radeon RX 6600/6700/6800 XT: RADV vs. PRO Vulkan Driver Performance

With yesterday’s launch day Radeon RX 6600 XT Linux review the benchmarks were conducted using the popular Mesa RADV open-source driver used by many Linux gamers considering it’s the driver Valve has been relentlessly optimizing and is the default on most (or all) Linux distributions. For those wondering how the performance of RADV is comparing to that of AMD’s closed-source “PRO” Vulkan driver distributed as part of the “Radeon Software for Linux” package, here are some benchmarks exploring that difference.

Today’s article is looking at the performance of the latest Mesa RADV performance using Mesa 21.3-devel (via the Oibaf PPA for easy reproducibility) and Linux 5.14 upstream Git against the latest Radeon Software for Linux 21.30 “PRO” driver stack that introduces support for the RX 6600 XT. The 21.30 driver stack released yesterday offers their latest look at their closed-source Vulkan driver that shares its code-base with the AMD Windows Vulkan driver and their closed-source shader compiler back-end.

There is also the AMDVLK open-source Vulkan driver from AMD that does share common code with their “PRO” Vulkan driver but leverages the AMDGPU LLVM shader compiler rather than their internal, closed-source shader compiler back-end. There will be some fresh benchmarks with AMDVLK included next week as well as a fresh look at the RADV performance when forcing on the NGG Culling feature recently merged.

The Radeon RX 6600 XT / RX 6700 XT / RX 6800 XT were tested between this latest upstream open-source and Radeon Software for Linux “PRO” Vulkan driver (including its DKMS kernel driver AMDGPU backport). Unfortunately, I still have no Radeon RX 6900 XT which is why that graphics card hasn’t ever been benchmarked on Phoronix.

All of the benchmarks were running off Ubuntu 20.04 LTS. Following some recent Radeon Software for Linux Vulkan driver tests on Ubuntu 21.04, I was informed by AMD there are currently some known performance issues when using their Vulkan driver in a Wayland environment. With time their Wayland issue should be addressed while for now they recommend users stick to running the packaged driver on the supported enterprise Linux distributions.

Hands On With The AMD Radeon RX 6600 XT

After the AMD Radeon RX 6600 XT was announced last week and ahead of the retail availability next week, today AMD’s “unboxing embargo” has expired for this new RDN2 graphics card focused on delivering high 1080p frame rates. The card we have been testing out under Linux is the ASRock Phantom Gaming RX 6600 XT.

With today’s embargo lift just being around the product unboxing, we aren’t yet allowed to talk about the performance of the Radeon RX 6600 XT but can at least show the card… And needless to say, AMD wouldn’t have sent out this graphics card to us if the Radeon RX 6600 XT wasn’t working under Linux or had major problems. So that alone speaks to the Linux support, but of course more on that next week.

As a reminder, the Radeon RX 6600 XT is launching at $379 USD given today’s graphics card climate and is focused on delivering superior 1080p performance. The RX 6600 XT based on the earlier announcement should be competing with the NVIDIA GeForce RTX 3060 series and deliver much greater uplift than the RX 5600 XT or RX 5700 Navi cards.

The Radeon RX 6600 XT Linux support is under the “Dimgrey Cavefish” codename. The open-source Dimgrey Cavefish work dates back to September 2020 and with the kernel-side AMDGPU driver premiered in Linux 5.11 and has seen improvements in succeeding kernels. Likewise, Mesa 20.3 added Dimgrey Cavefish with RDNA2 / Dimgrey improvements across the Mesa 21.x releases. But regardless what version of the Linux kernel and Mesa you are on, AMD has been in good rhythm of releasing new Radeon Software for Linux packaged drivers around launch day for supporting new GPUs on enterprise Linux distributions. Long story short, you can expect Linux driver support for the RX 6600 XT with all the details next week.

Learn more on 11 August and stay tuned for the Linux benchmarks on Phoronix.

If you enjoyed this article consider joining Phoronix Premium to view this site ad-free, multi-page articles on a single page, and other benefits. PayPal tips are also graciously accepted. Thanks for your support.

AMD Radeon RX 6600 XT Launching For 1080p RDNA2 Gaming At ~$379 USD

AMD just lifted the embargo on the Radeon RX 6600 XT, its newest entry in their RDNA2 line-up and optimized for delivering a superior 1080p gaming performance against the NVIDIA GeForce RTX 3060 series. The RX 6600 XT isn’t hitting retail availability until August and that is when we’ll be able to publish benchmarks, but for now here is an overview of this new graphics card launching at the $379 price point.

The Radeon RX 6600 XT graphics card features 32 compute units, 8GB of GDDR6 video memory, a 32MB infinity cache, and a 2359MHz game clock. This RDNA2 graphics card has a 160 Watt TDP and thus requires just a single 8-pin PCIe power connector. During AMD’s press briefing on the RX 6600 XT it was brought up repeatedly that the focus of the RX 6600 XT is on delivering a superb 1080p gaming experience.

Given the continuing popularity of the GeForce GTX 1060 graphics card, AMD referred to the RX 6600 XT as delivering up to 2.5x more performance. Or gen over gen, the RX 6600 XT is 1.4~1.7x faster than the RX 5600 XT or RX 5700 Navi cards.

AMD’s Windows-based figures put the Radeon RX 6600 XT at roughly up to 15% faster on average than the GeForce RTX 3060. It will be interesting though to see how the performance compares under Linux once getting our hands on the card and being able to share those performance numbers.

Perhaps the biggest surprise of the Radeon RX 6600 XT presentation was the price… $379 USD for this 1080p focused card. Back in the day, the GeForce GTX 1060 launched at $250 USD. Or even just a generation ago the RX 5600 XT pricing started out at around $280 USD. AMD acknowledged that this suggested retail pricing on the RX 6600 XT is driven by the current market conditions and they opted for setting a realistic price versus putting an artificially lower price knowing full well the prices for what other graphics cards are commanding these days and retailers would likely otherwise mark-up the card pricing themselves. AMD will be monitoring the market conditions and will be adjusting accordingly. They are also working on ensuring there is sufficient supply of the Radeon RX 6600 XT, but we’ll see how that goes once these cards launch in August. AMD isn’t releasing a reference card of the RX 6600 XT but relying on their AIB partners.

Stay tuned for our plethora of Linux benchmarks of the AMD Radeon RX 6600 XT starting 11 August.

If you enjoyed this article consider joining Phoronix Premium to view this site ad-free, multi-page articles on a single page, and other benefits. PayPal tips are also graciously accepted. Thanks for your support.

Open-Source Radeon Tools Updated With Expanded RDNA(2) Support, Other Features


In addition to NVIDIA releasing new open-source GameWorks projects this week for the Game Developers Conference, AMD with their GPUOpen initiative has released several updated Radeon Windows/Linux tools.

Radeon GPU Analyzer 2.5 is out today with expanded RDNA2 support (GFX1032 target support), support for analyzing OpenCL on RDNA/RDNA2/CDNA targets, live VGPR analysis and control-flow graph support within the Vulkan path, and a variety of other bug fixes and improvements to this graphics analyzer.

Radeon Memory Visualizer 1.2 is also out with stability and bug fixes, tooltips to supply more information, and range-based address search for resource tables.

Radeon GPU Profiler 1.11 was also released today. Radeon GPU Profiler 1.11 brings support for additional RDNA2 GPUs, cache counter support for OpenCL applications, ray-tracing handling improvements, faster loading of profiles, and other changes.

Details on these update tools and the other open-source Radeon packages for developers via GPUOpen.com.