SDRAM v DRAM chips on a 2019 iMac

I currently have 16 gb of Apple installed memory on my 2019 (2x8gb). Because I constantly have both Safari and Chrome open with an ever increasing number of tabs open as well, I would like to upgrade to 48 gb of memory, retaining and supplementing the capacity of my Apple installed chips. When I look on-line for Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of the following criteria:

PC4-21333, Unbuffered, Nonparity, 260-pin, and 2666MHz DDR4 SDRAM, the closest chips to these criteria that I find are chips that are rated at 2666 MHz DDR4 DRAM, rather than 2666 MHz DDR4 SDRAM.

I understand that SDRAM chips are faster than DRAM. If I purchase DRAM instead of SDRAM, will I notice the difference? Will my iMac work with DRAM chips?

Thanks,

Jim