Thermal Grizzly’s direct-die block uses €500 diamond sheets, aiming for 3-4x heat transfer

Thermal Grizzly’s Computex 2026 booth had a prototype that reads like a high-performance fever dream: an experimental direct-die CPU block for AMD AM5 that uses CVD diamond sheets right on top of the Ryzen 9 9950X’s CCDs. The most eye-popping line from Senior Marketing Manager Sasha Robey is also the one that will make procurement and product leadership sit up: each diamond insert costs around €500, and Robey estimates the full block would run €1500 or more.

The prototype’s cooling claim is equally bold. Robey says the block’s thermal conductivity is “three or four times better than normal blocks the industry is using,” supported by the basic materials math Thermal Grizzly shares: copper is approximately 390 W/mK for typical applications, while its CVD diamond inserts are “up to 2200 W/mK.” This is not marketing fluff in isolation. It is a real engineering bet on one constraint thermal designers know well: heat must leave the hottest silicon fast, and traditional metal-only interfaces have limits.

What exactly is Thermal Grizzly building? The block is a direct-die design, meaning it sits directly atop the CPU silicon-hence the name. To reach the silicon, the CPU must be delidded, a process Robey describes as precarious. On the inside of the block, the cooling layout is split: the IO chip is cooled by lapped metal, while the two CCDs sit beneath two extremely thin diamond inserts. Those inserts are CVD diamond inserts, with CVD standing for Chemical Vapor Deposition. In “regular parlance,” the article notes this is lab-grown diamond, and the prototype uses a very thin sheet for thermal benefit.

There is also a chemical reality check baked into the hardware. Robey explains that to put the diamond inserts on the block, Thermal Grizzly needs a special metal coating, because otherwise liquid metal will not stick to the diamond. That detail matters for anyone building or scaling a product line: it tells you the company is not only sourcing an exotic material. It is also doing interface engineering, making sure the thermal path is bonded well enough to capture the conductivity advantage rather than losing it to poor wetting or adhesion.

Cost is the whole bottleneck here. Robey frames the project as personal and experimental, and she explicitly flags the price tag as the main reason it’s unlikely to reach market. With diamond inserts at roughly €500 each, and a rough total cost estimate of €1500 or more for the block, the prototype looks engineered to prove a concept rather than to satisfy mainstream buyers. In other words, even if the thermal performance is real, the business case runs into a familiar wall: enthusiasts will pay for performance, but only up to the point where the bill looks like an experiment instead of a product.

Still, Thermal Grizzly is not just showing off diamond. The next likely path to market is coatings. The company says future products will include new coatings for its non-diamond CPU and GPU blocks, and it is joined forces with Swiss company Platit to test a range of options: a carbon-based option (light gray), a nitride-based option (dark grey), and an oxynitride-based coating (rainbow). The operational problem Robey wants to fix is nickel-plating. She says nickel plating is “not great because of corrosion,” and that it can force long waits: the company ships blocks out for nickel plating, and it waits four weeks or more sometimes to get products back.

That’s a supply chain and throughput story disguised as a finish. If internal coatings or alternative processes reduce corrosion risk and eliminate multi-week outsourcing cycles, Thermal Grizzly can tighten lead times, improve inventory planning, and reduce the friction that slows launches. It also potentially lowers downstream warranty and customer support headaches tied to durability. Meanwhile, the rainbow option is getting attention for aesthetic and perceptual reasons: Robey says “Everybody likes the rainbow one,” and it looks like rainbow because the film is so thin that light reflects in a way that appears rainbow-like.

For executives watching this, the strategic stake is simple: Thermal Grizzly is using an extreme prototype to explore boundaries, while preparing a more scalable product upgrade that targets a repeatable bottleneck (coating quality, corrosion, and processing time). The diamond block may never make it to market, but the coatings work likely will, and the competitive signal is clear. In high-end hardware, differentiation is not only raw cooling capacity. It is also manufacturability, reliability, and speed to ship.