Thermal Grizzly Mycro Pro Stainless Steel AMD AM4 AM5 (TG-MY-P-ST-001)

Thermal Grizzly's Mycro Pro Stainless Steel AMD AM4/AM5 is a CPU water block for AMD Socket AM5 and AM4 (AM5 Mycro Pro ST).

Properties

• Sockets: AMD AM5, AM4
• Cold plate: Unplated copper, 68 microfins at 0.2 mm
• Top: Stainless steel (S304)
• Frame: Anodized aluminum
• Ports: 2x G1/4, 6 mm deep
• Weight: 400 g, 577 g boxed

How it is built

The block consists of three primary components: a copper base plate, a stainless steel cooler plate that forms the body, and an anodized aluminum frame. It is connected to a custom water-cooling loop via two ports in the stainless steel body, one inlet and one outlet, both with standardized G1/4-inch threads. The sealing rings (O-rings) are made from EPDM (ethylene propylene diene rubber), which is highly elastic and resistant to ozone and UV radiation.

Direct heat transfer

The cold plate is bare copper. It is not nickel-plated, and Thermal Grizzly left the plating off in order to provide the best possible transfer of heat from the processor into the loop. Since the block is mounted on the Integrated Heatspreader (IHS), where liquid metal is generally not used, a barrier layer formed by nickel is not necessarily required. Eliminating the nickel-plating process from the manufacturing chain also reduces the production cost of the cooler, resulting in what Thermal Grizzly calls a very good price-to-performance ratio. The trade is looks. While bare copper slightly improves performance compared with a nickel-plated cold plate, it may discolor due to oxidation. Skin contact accelerates the oxidation and the resulting discoloration, so the block should only be handled by the anodized aluminum frame.

Ultra-High-Performance Coldplate

Thermal Grizzly's Ultra-High-Performance Coldplates, used on its CPU and graphics card water blocks, are milled with minimal and highly optimized channel and fin widths. In the case of this block, the channel and fin widths on the unplated copper are each 0.2 mm, and a total of 68 microfins are located on the base plate. This high number of thin fins provides the coolant with a very large surface area, across which it can dissipate heat quickly and efficiently. In Thermal Grizzly's in-house test, on a Watercool MO-RA3 radiator, the block held a Ryzen 9 9900X fixed at 5.3 GHz and 1.3 Vcore at an average 73.2 °C under full load. That is approximately 230 watts at a flow rate of 2.4 l/min, almost twice the 120 watts AMD gives for an unmodified 9900X.

Fit and product-specific notes

The block is compatible with the AM5 High Performance Heatspreader. It is not suitable for Direct-Die use, so it belongs on a CPU that still has a heatspreader. The G1/4-inch threads of the inlet and outlet ports are each 6 mm deep, and with two ports the block takes two compression fittings, such as the DeltaMate 16/10.

Mounting uses the motherboard's own backplate: the four standoff screws go in where the cooler retention brackets were. The block then sits on those screws over the thermal paste, followed by the springs, washers and thumb nuts. Tighten the nuts evenly in a crosswise pattern with the 2.5 mm Allen key, to a torque of up to 0.15 Nm.

In the box

• Mycro Pro Stainless Steel block
• 4x thumb nuts
• 4x #6-32 standoff screws
• 4x steel springs
• 4x polyamide M4 washers
• Allen keys, 2 mm and 2.5 mm
• Pressure test certificate (600 mbar)