AMD’s brand new RDNA 2 architecture has arrived for desktop PCs via the RX 6000 line of graphics cards – and it’s an important release, bringing with it full hardware support for the DirectX 12 Ultimate feature set, including the DXR API. Yes, ray tracing is now part and parcel of AMD’s high-end parts, and we wanted to get a grip on just how effective the Radeon rendition of the technology is in the RX 6800 XT – and how it compares to its closest rival, the RTX 3080. Benchmarks have shown that Nvidia’s second generation technology is faster than AMD’s debut offering, but what’s the full story here?
To help put this piece together, XFX sent me a factory overclocked example of the RX 6800 XT, specifically the Speedster Merc 319 edition of the card. Using its own tri-fan cooler design, this monstrous card delivers boost clocks rated at 2340MHz, around five per cent higher than the reference model, but I’ve seen it routinely reach clocks in the 2400MHz range and beyond. While the XFX card has new brand, the design philosophy has much in common with its previous ‘THICC’ range. The cooler is certainly similar, and does a good job in keeping temperatures at the low 70s Celsius range under load. As I mentioned though, it is somewhat beastly in term of form factor. Certainly in terms of its sheer bulk, you need to ensure you have adequate clearance in your case – it’s around 34cm or 13.5 inches in length!
In terms of the actual ray tracing metrics, it’s best to refer to the video here for the full breakdown of how I tested individual RT effects and how well they are handled on each of our competing GPU architectures, but the key objective of this testing was to isolate individual stages of the RT pipeline to see how Nvidia and AMD perform, and to do so within the context of three key RT effects: shadows, reflections and global illumination.