AMD Ryzen 4000: Renoir's Memory Controller Is Scary Good

It isn't every day that you see an AMD APU grace the headlines of the overclocking world, but an extreme overclocker recently hit DDR4-6234 on the newly-announced Ryzen 7 Pro 4750G. It might be short of the DDR4 memory world record, but the octa-core APU has demonstrated that it can hang with the big dogs. 

AMD dropped two bombs on the hardware world today. The chipmaker finally revealed the Ryzen 4000-series (codename Renoir) APUs for the desktop, but ultimately broke enthusiasts' hearts with the announcement that the APUs are only for OEMs. AMD did promise new APUs for the DIY market, but didn't commit to a firm release date.

Current Ryzen 3000-series (codename Matisse) processors can run the Infinity Fabric (FCLK) with the memory clock (MCLK) in a 1:1 ratio up to 1,800 MHz or DDR4-3600. The chips can support faster memory speeds, but that comes at the cost of asynchronous operation, which produces a latency penalty. Before desktop Renoir's debut, there were rumors that the APUs had a better IMC (integrated memory controller) that supports an FCLK up to 2,000 MHz, thus opening the possibility to run DDR4-4000 modules in a 1:1 operation.

Unfortunately, AMD's slides on Renoir don't confirm or dispel the FCLK rumors, and the chipmaker didn't provide many technical details about the Zen 2 APUs during the briefing. The Ryzen 7 Pro 4750G's feat isn't sheer confirmation of a better IMC, but it's impressive nonetheless since it's not common to see APUs breaking the top ten in memory overclocking.

Mini-ITX motherboards are popular among memory overclockers because of the shorter traces from the memory slots to the processor. As such, the overclocker paired the Ryzen 7 Pro 4750G with an Asus ROG Strix B550-I Gaming motherboard that provided an easy path to hitting 6,234.8 MHz on the memory.

According to the YouTube video, the overclocker used a single stick of Crucial-branded DDR4-5100 memory with a capacity of 8GB. The part number BLM8G51C19U4B.M8FN1 showed up on MSI's memory support list for the MPG B550 Gaming Carbon WiFi motherboard. It's a single-sided module that leverages Micron's N-die chips and runs at 1.45V. To hit DDR4-6234, the overclocker loosened the timings to CL24-27-27-58 T1.

It's a shame that AMD only released the desktop Renoir chips to OEMs for now. The Zen 2 chips certainly breathe new air into the processor market, but sadly, AMD decided to torture DIY enthusiasts with another long wait.