Radeon HD 7950 Video Card (MSI R7950-3GD5/OC BE)

This video card built around a Radeon HD 7950 chip is roughly ten years old. It is so outdated, nobody would pay much for a used unit on eBay. Not even at the height of The Great GPU Shortage. I’ve been keeping it around as a representative for full sized, dual-slot PCIe video cards as I played with custom-built PC enclosures. But I now have other video cards that I can use for the purpose, so this nearly-teenager video card landed on the teardown bench.

Most of its exterior surface is covered by a plastic shroud, but the single fan intake is no longer representative of modern GPUs with two or three fans.

Towards the center of this board is a metal bracket for fastening a heat sink that accounted for most of the weight of this card. In the upper left corner are auxiliary PCIe power supply sockets. The circuit board has provision for a 6-pin connector adjacent to an 8-pin connector, even though only two 6-pin connectors are soldered to this board. Between those connectors and the GPU itself, I see six (possibly seven) sets of components. I infer these are power-handling parts working in parallel to feed a power-hungry chip.

This was my first 4K UHD capable video card, which I used via the mini-DisplayPort connectors on the right. As I recall, the HDMI port only supported up to 1080p Full HD and could not drive a 4K display. Finally, a DVI port supported all DVI capabilities (not all of them do): analog VGA on its DVI-A pins, plus dual-link DVI-D for driving larger displays. I don’t recall if the DVI-D plug could output 4K UHD, but I knew it went beyond 1080p Full HD by driving a 2560×1600 monitor.

The plastic shroud was held by six plastic screws to PCB and two machine screws to metal plate. Once those eight fasteners were removed, shroud came off easily. From here we get a better look at the PCIe auxiliary power connectors on the top right, and the seven sets of capacitors/inductors/etc. that work in parallel to handle power requirements of this chip.

Four small machine screws held the fan shroud to the heat sink. Fan label indicates this fan consumes up to 6 Watts (12V 0.5A) and I recall it can get move a lot of air at full blast. (Or at least, gets very loud trying.) It appears to be a four-wire fan which I only recently understood how to control if I wanted. Visible on the fan’s underside is a layer of fine dust that held on, despite a blast of compressed air I used to clean out dust bunnies before this teardown.

Some more dust had also clung on to these heat sink fins. It seems like a straightforward heat sink with stamped sheet metal fins on an aluminum base, no heat pipes like what we see on many modern GPUs. But if it is all aluminum, and there are no heat pipes, it should be lighter weight than it is.

Unfastening four machine screws from the X-shaped rear bracket allowed me to remove the heat sink, and now we can see the heat sink has a copper core for heat distribution. That explains the weight.

The GPU package is a high-density circuit board in its own right, hosting not just the GPU die itself but also a large collection of supporting components. Based on the repeated theme of power handling, I guess these little tan rectangles are surface mount capacitor arrays, but they might be something else.

Here’s a different angle taken after I cleaned up majority of thermal paste. An HD 7950 is a big silicon die sitting on a big package.

When I cleaned all thermal paste off the heatsink, I was surprised at its contact surface. It seems to be the direct casting mold surface texture with no post-processing. For CPU heatsinks, I usually see a precision machined flat surface, either milling or grinding. Low-power/low-cost devices may skip such treatment for their heatsinks, but I don’t consider this GPU as either low power or low cost. I know this GPU dissipated heat on par with a CPU, yet there was no effort for a precision flat surface to maximize heat transfer.

I think this is a promising module for reuse. Though in addition to the lack of precision flat surface, there’s another problem that the copper core is slightly recessed. The easiest scenario for reuse is to find something that sticks up ~2mm above its surrounding components, but not by more than the 45x45mm footprint of this GPU. This physical shape complicates my top two ideas for reuse: (1) absolute overkill cooling for a Raspberry Pi, or (2) retrofit active cooling to the passively-cooled HP Split X2. If I were to undertake either project, I’d have to add shims or figure out how to remove some of the surrounding aluminum.

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