Should I buy DDR4 or DDR5 RAM for a new PC build?

Go with DDR5. It’s the safer long-term bet because future sockets like Intel’s next-gen and AMD’s AM5 are DDR5-only, and the price difference is now only $20-30 for a 32GB kit. You’ll get better performance now and avoid being stuck with unusable RAM in two years. Only stick with DDR4 if you’re on a tight budget building a low-end machine.