Samsung's HBM3E chips had overheating issues, which is the reason they didn't pass Nvidia's quality benchmarks. By the time its HBM3E chips were redesigned, SK Hynix captured a majority of market share, and Micron became the second biggest supplier. While Samsung's redesigned HBM3E chips finally received Nvidia's approval, it had to lower the prices of those chips by 30% compared to its rivals.
Samsung then invested significant effort and money to develop its HBM4 chips. While Micron and SK Hynix used 1b DRAM chips for their HBM4 chips, Samsung opted for 1c DRAM. It uses the 10nm-class 6th generation process to make core DRAM chips. These chips are then stacked to form an HBM4 chip. The finer circuit line width of 1c DRAM is expected to enhance the speed and power efficiency compared to 1b DRAM (10nm-class 5th generation process). So, Samsung's HBM4 chips are expected to outperform those from its competitors.