Ryzen 7 7800X3D Breaks Barriers: L3 Cache Achieves Remarkable Speeds

AMD’s X3D series processors employ the 3D V-Cache technology, which involves stacking an additional layer of SRAM on top of the CPU’s CCD. This innovation grants the CPU a substantially larger L3 cache, significantly enhancing the instruction hit rate. This feature is particularly beneficial for applications sensitive to latency. However, there are enthusiasts who have explored using this enlarged L3 cache as a Ramdisk.

@Albert Thomas shared a CrystalDiskMark (CDM) screenshot showing astonishing results achieved with the L3 cache of a Ryzen 7 7800X3D. The continuous read speed reached an impressive 178GB/s, with a continuous write speed of 163GB/s. The 4K QD1 random speed also hit remarkable heights of 1613MB/s and 1185MB/s, effortlessly surpassing the speeds of PCIe 5.0 SSDs and multiple times faster than Intel’s Optane.

The method, provided by @Nemez, involves using the OSFMount software to create a FAT32 format Ramdisk, then running CDM and adjusting the settings to SEQ 256KB, queue depth 1, and 16 threads, with data filled with zeros instead of random values. Due to potential system loads, the first attempt might fail, necessitating several test runs. Furthermore, CDM can only run test data packets ranging from 16MB to 32MB.

However, the Ramdisk created using AMD’s 3D V-Cache is more of a novelty than practical. Even the Ryzen 9 7950X3D’s L3 cache, at 128MB, is not particularly useful as a hard drive. In contrast, Genoa-X, with its 1.3GB L3 cache, might present a more feasible option for such an application.