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AMD Radeon RX 6600 XT Review: The Memory Compromise

Navi 23 only has 8GB GDDR6 on a 128-bit interface

AMD Radeon RX 6600 XT
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AMD Radeon RX 6600 XT

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AMD Radeon RX 6600 XT

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AMD Radeon RX 6600 XT

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AMD Radeon RX 6600 XT

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AMD Radeon RX 6600 XT

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AMD Radeon RX 6600 XT

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AMD Radeon RX 6600 XT

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AMD Radeon RX 6600 XT

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So far, all of our gaming benchmarks have focused on traditional rasterization performance, but the RX 6600 XT also supports DXR, just like all other RDNA2 GPUs. What happens when you play a game that supports ray tracing? In some cases, like the AMD promoted Dirt 5 and Godfall, performance is still above 60 fps for the most part. Other times, it's not just the wheels falling off: The transmission drops to the ground, and the engine throws a rod for good measure.

Even without factoring in DLSS performance — which is still an advantage Nvidia holds over AMD — the RTX 3060 outperformed the RX 6600 XT by 52% across our ray tracing test suite at 1080p and by 70% at 1440p. Dirt 5 was the only game where AMD's GPU came out ahead, and as we've mentioned previously, the ray traced shadows in Dirt 5 aren't all that compelling an argument for ray tracing in general. We'd say the same about the shadows in Godfall and Shadow of the Tomb Raider; ray tracing is better suited to reflections and global lighting effects rather than shadows that can be 'faked' pretty nicely using faster algorithms.

Games with more ray tracing effects can really punish the RX 6600 XT. Bright Memory Infinite, Cyberpunk 2077, Control, and Minecraft all favor the RTX 3060 by anywhere from 30% (Bright Memory Infinite) to over 130% (Minecraft). And then there's Watch Dogs Legion, which seems to have some driver problems holding it back as it only managed 6.2 fps at 1080p — though that did improve to 8.6 fps when we tested on the Ryzen 5900X, so perhaps it's related to memory thrashing rather than just drivers. Still, the RTX 3060 Ti and other 8GB Nvidia cards didn't have that sort of difficulty.

The real concern is that across our suite of ten games that support ray tracing effects, only half of the games managed more than 30 fps at 1080p — and only Control managed more than 30 fps while using more than one RT effect. Actually, there's a second game with multiple RT effects that broke 30 fps on the 6600 XT: Metro Exodus Enhanced Edition, which ran at 38 fps (but we don't have a full suite of results on the other GPUs yet, so that's not in the charts).

Again, it's difficult to pinpoint whether the bottleneck is the 8GB of VRAM, the 128-bit memory interface, or the 32MB of Infinity Cache. It's probably all of those to varying degrees, with some missing driver optimizations also playing a role. It's worth pointing out how the RX 6700 XT basically destroys the RX 6600 XT as well. The 6700 XT was at most 37% faster overall in rasterization testing at 4K ultra. With ray tracing turned on, the 6700 XT was 54% faster at 1080p and 73% faster at 1440p. Except, a big part of that was the failed Watch Dogs Legion testing.

Navi 23 and the RX 6600 XT are now the lowest performance graphics card supporting ray tracing effects. Technically the RTX 2060 does perform a bit worse in several of the DXR games we tested, but the RTX 2060 also supports DLSS, which can make a big difference since most of the ray tracing games support it. RX 6600 XT is a foot in the ray tracing door, but unless some clever algorithms can drastically improve RT performance without dropping image quality, it's a card that's much better suited to traditional rasterization techniques.

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Jarred Walton is a senior editor at Tom's Hardware focusing on everything GPU. He has been working as a tech journalist since 2004, writing for AnandTech, Maximum PC, and PC Gamer. From the first S3 Virge '3D decelerators' to today's GPUs, Jarred keeps up with all the latest graphics trends and is the one to ask about game performance.