AMD’s new graphics cards from the Radeon RX 6000 series are really fast. Real-time beam calculation Ray tracing and AI renderer DLSS left out for once, the RX 6800 XT and Co compete at the top with their respective rivals from Nvidia.
It is particularly interesting that the balance of power shifts noticeably depending on the level of resolution. This is shown, among other things, by our following test of the RX 6900 XT, the corresponding benchmark results can be found on page 2:
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Radeon RX 6900 XT im Test
The lower the resolution, the better for AMD
In 4K, the RTX 3090 is still clearly at the top, the RX 6900 XT and RTX 3080 are roughly on par. In WQHD, on the other hand, the RX 6900 XT comes very close to the RTX 3090 and in Full HD it even takes the lead.
Of course, it is important to keep in mind that in Full HD the CPU can become the limiting factor. Let’s take a look at the measurements of individual games (you can also find these values in the test for the RX 6900 XT linked above on page 2):
- Anno 1800 and Metro Exodus: Here, the RX 6900 XT and RX 6800 XT in Full HD are noticeably faster than the Nvidia graphics cards (+9, +8 percent and +20, +13 percent compared to RTX 3090 / RTX 3080).
- Assassin’s Creed: Odyssey: Here the Radeons are clearly behind (-23 and -24 percent compared to the RTX 3080), in all other cases the CPU limits.
The colleagues at Chips and Cheese have now found a possible reason why the new Radeons are often faster than the competition at lower resolutions.
The cache should make it all
For this purpose, Chips and Cheese measured and compared the memory latency, i.e. the signal propagation time or delay of the cache of the RDNA2 and the Ampere architecture (RX 6800 XT and RTX 3090).
Although AMD uses a cache system with four levels (L0, L1, L2 and Infinity Cache / L3 cache) and thus two cache levels more than Nvidia (only L1 and L2), the overall latency is lower on the Radeons. The reason for this could be that Nvidia’s chips are larger than AMD’s, which means that the signals have to travel longer distances.
What is a cache? Caches are small intermediate stores. The lower the level, the smaller and faster the cache. Higher cache levels become slower because they have to serve several components at the same time, which increases the signal runtimes.
How does fast cache affect games?
The lower the resolution and the higher the frame rate, the greater the influence of the latencies of the individual caches on performance. Therefore, Chips and Cheese suspects that this factor explains the very good performance of the Radeons at lower resolutions.
Another reason is the high clock speed of the Radeons. Here, AMD has a clear lead over Nvidia, which is also noticeable at lower resolution levels. However, it should be noted that the new cards are especially suitable for high resolutions because of the CPU limit mentioned, which puts these advantages into perspective.
Nvidia, on the other hand, can show its strengths especially with higher resolutions, since parallelization is more important here and RTX 3000 simply offers more computing cores.
The advantages in terms of cache could help AMD especially with slower RX-6000 cards that are generally designed for gaming in lower resolutions. It is still uncertain whether and when possible models such as an RX 6600 (XT) or RX 6500 (XT) will appear.
The real reasons for the hardware shortage
The persistently poor hardware availability should not be forgotten either, which we discuss in more detail in the video linked above. AMD is particularly affected because the chips in the new PlayStation 5 and Xbox Series X / S consoles are also from AMD. That should make the release of new Radeon GPUs even more difficult.