Nvidia has published a video report on the development process of the GeForce RTX 5090 Founders Edition video card. One of the prototypes had a vertical printed circuit board design and occupied the space of four slots – fortunately, the company managed to shrink the design to a two-slot height, which has been preserved to this day.
Image source: youtube.com/@NVIDIAGeForce
The company’s engineers assembled a bulky prototype while experimenting with a “flow-through” cooling scheme—air flows freely through the entire video card. The company first used a cooler with this design in the GeForce RTX 30 series video cards, kept it in the RTX 40 series, and now decided to develop the idea by choosing coolers with “three-thirds flow” for the RTX 50 series. That is why this prototype has already appeared several times in leaks, which attributed it to the RTX Titan Ada or RTX 4090 Ti.
The board in the shown prototype was turned vertically, and three fans were placed in a stepped pattern: the top one was on the right, the bottom one was on the left, and the middle one was framed by radiators at the top and bottom. Nvidia management apparently rejected the project, saying that such a video card was too bulky and would only work in a limited number of cases.
However, the company’s engineers learned some lessons from the project and adapted its positive aspects to the features of the Blackwell architecture. With the GeForce RTX 5000 series, they simplified the design from “three-thirds flow” to “two-thirds flow” – as a result, they were able to improve thermal performance and reduce the height of the video card to two PCIe slots.
A major problem was also the assembly of the flat cable connecting the external DisplayPort 2.1b (UHBR20) and HDMI 2.1b ports – the company used fiberglass to obtain the required connection reliability. Finally, Nvidia engineers had to work hard to confirm the reliability of the liquid metal thermal interface. They tested the design in all orientations and used an airtight seal to prevent the liquid metal from oxidizing and leaking from the GPU die area – this is important because liquid metal is conductive and if it gets on the board, it can damage the graphics card.