Which 32GB kit should you buy?
Start with your motherboard, not with this table. A board for DDR5 only takes DDR5 modules and a DDR4 board only takes DDR4: the notch in the module sits in a different place, so the wrong type does not even go in. The manual or the product page of your board lists the type and the speeds it supports.
For a new build on AMD AM5 or a recent Intel platform, buy a kit of two 16GB DDR5 modules. AMD has said that DDR5 6000 is the sweet spot for its Ryzen 7000 processors, and CL30 is the common latency at that speed. Faster kits cost more and rarely show a difference in games. If a kit at 5600 or 6400 MT/s is clearly cheaper this week, that is a fine choice too. Use the speed filter above the table to compare.
Enable the XMP or EXPO profile in the BIOS after you install a new kit. Without it, most kits run at a slower default speed.
Is DDR4 still worth it for 32GB?
Only if you keep your current DDR4 board. On an older system, a 32GB DDR4 kit at 3200 or 3600 MT/s with CL16 to CL18 is the sensible range. Adding a second matching kit to an existing one can work, but two kits are not tested together, so they sometimes refuse to run at their rated speed. One kit with the full capacity is the safer buy.
Avoid a single 32GB module on a desktop unless you plan to add a second one later. Two modules run in dual channel, and that matters more for speed than a few hundred MT/s.
How to read this table
The table shows every 32GB desktop kit we found this week, cheapest first, with the price per GB under each price. Kits marked out of stock are hidden until you untick the stock box. The highlighted row has the lowest price per GB. Prices are excluding sales tax; the final price, with shipping, is the one at the shop's checkout.