DDR4 vs DDR5 for a budget build in 2026: the real maths

"Is DDR4 still worth it in 2026?" is one of the most-searched PC questions this month, and the honest answer used to be "no, buy into AM5." The memory shortage changed that. When 32GB of DDR5 costs more than the CPU and motherboard combined, the old platform deserves a second look. So I priced both builds, part by part, on the same day, with new-condition stock only, and did the maths.

The two builds, priced on 25 September 2026

All prices are from Amazon US with a New York delivery address, checked on 25 Sep. I used new-condition offers only, and I've named the seller, because several of the cheapest listings were third parties or used units. I left out the GPU, SSD, PSU and case because they're the same either way.

That's the surprise in the maths. The AM5 CPU barely costs more: a new Ryzen 5 9600X was only $21.96 above a new Ryzen 5 5600 from third-party sellers that day. The board adds $40. The memory adds $240. In 2025 you'd have told me AM5's premium was the platform. In 2026 it's almost entirely the RAM.

Is DDR4 really ~56% cheaper per GB? The maths

You'll see "DDR4 is 56% cheaper per gigabyte" quoted around the web. I wasn't going to repeat it without re-pricing it, so here it is from primary data: the Amazon prices I checked, plus the best US prices in Tom's Hardware's RAM price index (updated 14 Sep 2026).

• Budget kit vs budget kit (Amazon): $6.56 vs $14.06, so DDR4 is 53% cheaper per GB.
• Mainstream vs mainstream (Amazon, Corsair vs Corsair): $7.81 vs $14.69, so 47% cheaper.
• Best US prices (Tom's index): $5.94 vs $12.78, so 54% cheaper.

So the claim is close. DDR4 is roughly 47–54% cheaper per GB, depending on which kits you compare. That's still a huge gap, but "about half price" is the honest way to say it. For context, Tom's Hardware notes that 32GB DDR4 kits sold for $60–90 in October 2025, so DDR4 hasn't escaped the shortage either. It's just been hit less hard.

What the extra $300 buys you on AM5

I'm not going to quote frame rates. I haven't benchmarked these builds, and borrowed numbers from different test rigs would mislead you. What I can give you is what's on paper and what's been officially committed:

The bandwidth numbers are plain spec arithmetic: two channels × 8 bytes × the transfer rate. That's 51.2 GB/s for DDR4-3200 and 89.6–96 GB/s for DDR5-5600 to 6000. For the socket, AMD confirmed at Computex 2026 that AM5 will be supported through 2029, while AM4's CPU lineup is what it is. You can still drop in a faster Ryzen 5000 chip later (the Ryzen 7 5800X3D was $349 sold by Amazon.com on 25 Sep), but that's the ceiling.

Who should buy which

• Budget gaming build, GPU-limited: AM4 + DDR4. Put the ~$300 into the graphics card, which usually matters more for frame rates than the CPU platform at this price.
• You already own DDR4 and an AM4 board: upgrade in place. Keep your RAM, swap the CPU, and skip the platform change entirely.
• You'll run local AI models that spill into system RAM: AM5 + DDR5. When a model doesn't fit in VRAM, CPU offloading speed follows memory bandwidth, and DDR5 has roughly 75–90% more on paper. Our MoE offloading guide explains why that matters.
• You want one platform for 5+ years: AM5. The 2029 support commitment is worth more than it costs if you'll swap CPUs later.

Timing the purchase is its own question. I've covered it with the full price history in RAM prices: Prime Day or Black Friday?. How much you actually need is in how much RAM for gaming, and for local AI, the system memory guide.