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AMD Ryzen 9 7900X and Ryzen 5 7600X review: welcome to the future

What difference does RAM speed make?

Will Judd avatar
Review by Will Judd Deputy Editor, Digital Foundry
Updated on

After taking a closer look at DDR4 versus DDR5 in analyses past, it's now time to focus entirely on DDR5. We've actually done more RAM testing than normal for a CPU review, as our previous Intel 12th-gen results were based on a DDR5-5200 system but AMD recommended (and indeed, provided) DDR5-6000 for our Ryzen 7000 testing. That meant we had to either accept an apples-to-oranges comparison, with Intel facing an unfair disadvantage with slower DDR5 RAM, or perform testing at both frequencies to keep things fair.

We opted for the latter - so we have 5200MT/s results across the board, plus 6000MT/s results for 12900K, 12600K, 7900X and 7600X. We also squeezed in 4800MT/s results for the three games on this page, to give you an idea of the performance you can expect with the cheapest possible DDR5 kits.

You've therefore seen the performance differential between 5200MT/s and 6000MT/s on all the games we've tested so far, so let's start this section with a new title: Ashes of the Singularity Escalation. This is a great DX12 game that absolutely lives and dies on CPU performance and fast RAM typically offers noticeable performance improvements. And indeed, we see a steady progression from 4800MT/s to 5200MT/s and then 6000MT/s. The AMD chips are slightly more RAM-sensitive than the Intel ones in this particular game, with a seven percent improvement from DDR5-4800 to DDR5-6000 for Team Blue and a 10 percent improvement for Team Red.

Ashes of the Singularity: CPU Test

Far Cry 6 is a game that is quite single-threaded, with a lot of processing limited to a single thread, so it's a good test of how faster RAM affects performance in this sort of a more thread-naïve title. The 7900X sees a massive 12 percent improvement from the faster RAM, while the 7600X's advantage is much more modest: two percent. Interestingly, we see a similar progression with the 12900K and 12700K.

Far Cry 6: Ultra, TAA

Crysis 3's benchmark turns in very reliable and repeatable performance, making it a good choice for seeing even minor performance variations. Here, the margin for the faster RAM is worth around four to five percent for both the 12900K/12600K and the 7900X/7600X pairings.

Crysis 3 Remastered: Very High, RTX, DLSS Perf

So DDR5-6000 does look like the performance sweet spot, as AMD predicted, but with a maximum of a 12 percent advantage the best value option remains base-spec DDR5-4800, even if you're leaving some performance on the table. If you're going for a high-end build throughout, then DDR5-6000 is worth going for, but if you're on a budget then opting for a higher tier GPU or CPU is likely to provide a more significant (and universally useful) speed-up.

So what are our final thoughts? Let's wrap it all up on the final page.

AMD Ryzen 9 7900X and Ryzen 5 7600X analysis