Intel Core i9 13900K and Core i5 13600K review: an effective redoubt against AMD's Ryzen 7000 advances

What difference does RAM speed make?

Review by Will Judd Deputy Editor, Digital Foundry

Published on 20 Oct 2022

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 DDR5-6000 for our Ryzen 7000 testing... so we ended up testing both frequencies. We've continued that tradition here.

Therefore, we have 5200MT/s results across the board, plus 6000MT/s results for 13900K, 13600K, 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. That's indeed the case here, with a pleasing step up at each configuration. We get an extra 2.5 percent moving from 4800MT/s to 5200MT/s, then a further four percent moving to 6000MT/s. That's a seven percent improvement altogether, and we see an even bigger 11.5 percent jump from DDR5-4800 to DDR5-6000 with the 13600K. I thought we might be able to crack a 60fps average here for the first time in years of testing, but we're still a little shy - maybe with 14th-gen?

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. Again, we see a small bump on the 13900K, but the 13600K is seemingly more sensitive to the extra RAM speed with nearly a six percent average frame-rate improvement overall.

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. As usual, we see quite modest improvements from faster RAM, with the 13900K 6000MT/s result being the only one that really stands out as being better-than-expected - and this is still only around three percent. Here, getting the cheapest possible RAM and saving the money for a higher-tier CPU or GPU makes the most sense.

Crysis 3 Remastered: Very High, RTX, DLSS Perf

So again, DDR5-6000 does provide a noticeable performance edge, but it's only in a small subset of games that you'll actually see a noticeable performance delta. DDR5-4800 or DDR5-5200 RAM is definitely the way to go for the immediate future then!

Before we conclude our thoughts, I thought it would be interesting to look at the Z790 platform as a whole - and our motherboard in particular. That analysis is on the next page!