Sapphire NITRO+ Radeon RX Vega 64 Limited Edition

A Closer Look At The Sapphire NITRO RX Vega 64 Internals

There are 13 screws that pass through the PCB to hold the backplate and cooler in place. The plastic shroud has a series of four tiny screws holding it to the heatsink. When you remove the shroud, you can see that the heatsink has two sections, one dedicated to dissipating heat from the GPU and HBM, and the other for the VRM. There are six nickel-plated heat pipes, three of which are 6mm in diameter, and the remaining three are 8mm in diameter.

Despite the three fans, five temperature sensors, and multiple RGB LEDs, just two power connectors tether the shroud to the PCB, and they came apart easily.

The heatsink is composed of densely packed aluminum fins, but instead of a mere block of copper at the heat pipe’s point of convergence, Sapphire has resurrected the Vapor-X vapor chamber, which uses a hollow chamber with phase-changing liquid to facilitate the exchange of heat between the GPU/HBM and the heatsink.

One of the massive advantaged of High Bandwidth Memory, as AMD is fond of pointing out, is the extremely efficient use of space on the PCB. But because the memory and GPU are effectively within a few millimeters of one another, there’s significantly more heat being generated in a much smaller area. Sapphire’s vapor chamber technology is the ideal solution for a strictly air-cooled Vega.

The VRM on the Sapphire NITRO+ RX Vega 64 consists of seven phases effectively doubled, for a 14-phase digital power design. This component of the card generates a lot of heat too, and Sapphire’s cooler features two dedicated 6mm heatpipes attached to a thick block of copper that makes direct contact with a majority of the VRM components. These heat pipes even have their own narrow heatsinks attaches to their ends, to help flush away heat when they’re under load.

You may have heard a bit about some Vegas shipping with height differences between the GPU die surface and the HBM die stack surfaces, causing the heatsinks to make uneven contact with the two components and throttling under excessive heat coming from the HBM. The Sapphire NITRO+ RX Vega 64 shipped with molded dies, which looks like a translucent epoxy-like substance is covering the GPU, HBM, and the gaps between them. As a result, we couldn’t detect a difference in component height, and our temperatures looked solid throughout testing, both before disassembly and after reassembly.

The black PCB is adorned with a nifty white circular design around the GPU/HBM and there are some angled white stripes around a Sapphire logo between the VRM and the fan- and lighting effect-managing Elan EM88F758N eight-bit microcontrollers on the right edge of the PCB. Although I won’t delve into the VRM components individually, I do want to point out the series of fifteen Black Diamond Chokes, above and to the right of the GPU/HBM.

Taking a look at the back of the PBC reveals the rather clever hunk of clear plastic that’s attached to the backplate. There are a series of LEDs surrounding a NITRO logo painted onto the PCB where the illuminated version shows through on the backplate. Other items of note on the back of the PCB include some voltage converters and a PWM controller.