Introduction

XFX Radeon RX 7900 XTX Speedster Merc 310 is the company’s flagship custom-design graphics card, based on AMD’s latest RDNA3 generation of graphics cards out to eat NVIDIA’s lunch in the high-end segment with aggressive pricing, and performance in league of NVIDIA’s fastest. Designed to resemble a muscle-car, the Speedster Merc 310 pairs the RX 7900 XT with a cooling solution that was uniquely designed and optimized for the GPU, given that XFX is an AMD-exclusive AIB, unlike other multi-brand AIBs reusing solutions originally designed for their NVIDIA GPUs. The Speedster Merc 310 uses a large vapor-chamber plate making optimized contact with the “Navi 31” GPU and the twelve GDDR6 memory chips, and eight 6 mm-thick heat pipes that convey heat to a continuous aluminium fin-stack that spans the entire length of the card, without breaks in the middle. This is ventilated by a trio of 100 mm dual-ball bearing fans, through an airy cooler shroud designed for minimal obstruction of exhaust from the heatsink. XFX also offers a few gamer-friendly features, such as a reinforcement brace that counteracts sagging of the graphics card over time, dual-BIOS, and factory-overclocked speeds of 2510 MHz game clocks, compared to 2455 MHz reference.

AMD surprised us a few years ago with its strong and unexpected comeback to the high-end gaming graphics segment with its Radeon RX 6000 series RDNA2, thanks to a 50% generational performance/Watt uplift. The only way AMD can remain competitive in this segment is to repeat the feat, which it claims to have succeeded in with its new RDNA3 graphics architecture, with a 54% performance/Watt uplift, without breaking the bank by using a large (expensive) 5 nm monolithic silicon. AMD incorporated the same chiplet packaging architecture philosophy it had with processors for several years now, onto GPUs, with the new “Navi 31” chiplet GPU. This helps AMD implement Moore’s Law in spirit, if not letter, by keeping the growth in price and power generationally flat, while improving performance. This is accomplished by identifying the components on the GPU that don’t benefit all that much from the transition to the 5 nm EUV process, and disintegrating them into chiplets built on the less-advanced 6 nm node. These would be the Infinity Cache memory, the memory controllers, and GDDR6 PHY. Everything else that does tangibly benefit from the new node, is nucleated into a large centralized die called the Graphics Compute Die (GCD), surrounded by six Memory Cache Dies (MCDs). Each MCD has a 64-bit GDDR6 memory path, and a 16 MB segment of the GPU’s 96 MB Infinity Cache. This may seem lower in amount compared to the 128 MB on the previous “Navi 21” GPU, but AMD has generationally increased memory bandwidth by as much as 87%, and can make do with smaller caches.

The new RDNA3 graphics architecture introduces a new dual instruction-issue compute unit, which incorporates support for new math formats, an AI accelerator for matrix math, and a 2nd generation Ray Accelerator. AMD claims a 17.5% IPC uplift for the RDNA3 CU. This, combined with higher engine clocks, a 20% increase in CU count, and the much faster memory sub-system, is how AMD is able to keep its generational performance/Watt growth as high as 53% over RDNA2, and stay competitive with NVIDIA’s RTX 40-series “Ada” high-end, without increasing prices. The RX 7900 XTX has a starting MSRP of USD $1,000, to which XFX has posted a $100 value-addition for the Speedster Merc 310 OC.

The Radeon RX 7900 XTX maxes out the “Navi 31” silicon, featuring all 96 RDNA3 compute units, working out to 6,144 stream processors, 384 TMUs, 96 Ray Accelerators, and a whopping 192 ROPs. The RX 7900 XTX is endowed with 24 GB of 20 Gbps-rated GDDR6 memory across a 384-bit memory interface, working out to an impressive 960 GB/s of memory bandwidth. AMD has decoupled the engine clocks of the GPU’s Front End and the Shader Engines, such that the Front End operates at a roughly 10% higher frequency. This contributes to power optimization. Speaking of which, AMD targets a typical board power of 350 W for the RX 7900 XTX, with the XFX Speedster Merc 310 only running it up to 339 W (can be increased). The card draws power from three conventional 8-pin PCIe power connectors, for a power-input configuration of 525 W (the additional power connector should help with spike suppression). XFX is pricing the Radeon RX 7900 XTX Merc 310 at $1,100, a $100 premium over the AMD MSRP.