Nvidia RTX 3080: PCIe 4.0 vs 3.0 scaling analysis

Concluding this article is relatively straightforward. As of right now, performance improvements to be had when using the RTX 3080 on a PCIe 4.0 interface are very small at best, and in many cases are simply non-existent.

That's not to say we didn't observe some difference. In a few games we tested – including Control with RTX On, Horizon Zero Dawn and Total War Saga: Troy – PCIe 4.0 can net up to 5% better performance versus the older PCIe 3.0 standard, when tested with a Ryzen 3900XT. The fact remains that these are best case scenarios, and even if we saw 5% gains in every single game, it's still not a big difference. The reality is many games simply do not care about PCIe bandwidth – at least not yet.

Right now, the choice of CPU is far more of a limiting factor for the RTX 3080. At 1080p, we observed the i9-10900K outperforming the 3900XT by 10% on average, while three games we tested had the difference over 20% in Intel's favour.

That means it's even harder to pin-point relative gains by switching to PCIe 4.0. The extra bandwidth seemingly helps most at 1080p, but that's the same resolution where Intel is able to outperform AMD by a not insignificant margin, muddying the waters somewhat. It's possible we will get a clearer idea of the true benefits of PCIe 4.0 if Zen3 is as fast as we hope it is, but that's all hypothetical at this point.

Then again, the differences at 1440p and 4K are much less significant. While our 3900XT system with PCIe 4.0 produced on average 2% higher frame rates than the same CPU with PCIe 3.0, the Intel system's lead was in turn reduced to just 3%. At 4K, the margins of difference grow even smaller.

For KitGuru, we will continue to use our i9-10900K test system for our reviews in the immediate future, but as games progress and we start to see more benefits to PCIe 4.0, we will no doubt have to make the jump sooner rather than later. Whether that is to an AMD Zen3-based test system, or an Intel Alder Lake machine, we will have to wait and see.

RTX 3080 Founders Edition has a UK MSRP of £649 and will be available for purchase directly from Nvidia HERE. Custom cards will be available from Overclockers UK starting at £649.99 HERE.

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KitGuru says: It's been fascinating to test the RTX 3080 on both Intel and AMD systems these last few days. Right now, PCIe 4.0 doesn't make much difference at all, but as technology and games progress it's only going to become more important for gaming.

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