Ryzen 5000 CPUs recommends DDR4-4000MHz system memory for best performance
AMD Phenom II X4 945 3 GHz HDX945WFK4DGM CPU Processor 4000 MHz Socket AM3 2 MB 789398906261 | eBay
G.Skill RipJaws V Series 16GB (2 x 8GB) 288-Pin SDRAM (PC4-32000) DDR4 4000 CL18-22-22-42 1.35V Dual Channel Desktop Memory Model F4-4000C18D-16GVK at Amazon.com
Patriot Viper Steel 4000 MHz CL19 DDR4 review - CPU-Z – DDR4 with a Core i7 processor, with XMP enabled
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Intel Core i5 @ 4000 MHz - CPU-Z VALIDATOR
Patriot Viper Steel 4000 MHz CL19 DDR4 review - CPU-Z – DDR4 with a Core i7 processor, with XMP enabled