The Radeon RX 6600, one of the best graphics cards on the market, has emerged in a rare MXM (Mobile PCI Express Module) form factor. Redditor SurfaceDockGuy has somehow acquired a Radeon RX 6600 MXM and tore it down to examine its interior. While the MXM form factor typically is found inside laptops, this particular Radeon RX 6600 module is probably for eGPU enclosures or servers that accept the format.
AMD's Navi 23 silicon, which measures 237 mm², resides at the heart of the Radeon RX 6600. The Redditor noted that the Radeon RX 6600 MXM utilizes a 10-phase power delivery system with what appears to be two NCP81022 4+1 voltage controllers in tandem. Therefore, It's plausible that seven phases power the Vcore, whereas the remaining three phases cater to the GDDR6 or SoC. Furthermore, an integrated OnSemi 55A power stage administers each phase, as SurfaceDockGuy reckons. Therefore, it would seem that HIS (Hightech Information System Limited) is the manufacturer behind the Radeon RX 6600 MXM.
According to the Redditor, the AMD driver detects the MXM as a vanilla Radeon RX 6600, so the number of stream processors is intact. In addition, it arrives with four 16Gb Micron GDDR6 memory modules. However, the TDP is substantially lower, given the compact form factor. The firmware reportedly fixes the TDP at 75W. For comparison, the desktop Radeon RX 6600 features a 132W TDP, whereas the mobile Radeon RX 6600M sits at 100W. Therefore, the MXM variant is the slowest of the trio. However, the Redditor could unlock the power limit via MorePowerTool, a popular Radeon tweaking, and overclocking tool, and set the TDP past 130W.
SurfaceDockGuy didn't provide any benchmark results for the Radeon RX 6600 MXM. However, he claims that it matches the performance of a desktop Radeon RX 6600. So it makes sense the Redditor pushed the MXM over 130W, which puts it in the same alley as the regular Radeon RX 6600 with a 132W TDP rating.
The Radeon RX 6600 MXM comes with a cooling system that consists of a heatsink, three copper heat pipes, and a tiny 40mm cooling fan from FirstD. SurfaceDockGuy highlighted that the performance is on par with his desktop Radeon RX 6600, which features a three times larger heatsink and double cooling fans. The PCB lacks a fan header, so the 40mm fan connects to a host controller board on the flipside of the MXM interface.
It's not surprising that vendors still offer the latest-generation graphics cards in the MXM format. There are a few Nvidia Ampere MXM offerings on the market, but they target the professional market with models such as the RTX A4500 or RTX A2000. Therefore, it's the first time we've seen one of AMD's Radeon RX 6000 (Big Navi), a gaming graphics card, arrive in an MXM form factor.
