Friday, July 4th 2025
PCIe Bottlenecks Slash NVIDIA GeForce RTX 5090 Content Creation Performance by 25%
A lack of PCIe bandwidth can reduce RTX 5090 performance by as much as 25% in video editing and 3D workloads. Puget Systems conducted a series of tests on NVIDIA's GeForce RTX 5090, comparing different PCIe versions and lane configurations to assess the impact on content creation tools. At its launch, TechPowerUp's scaling tests noted that the GeForce RTX 5090 is the first high-end card to adopt PCIe 5.0 x16, delivering 64 GB/s of bidirectional bandwidth—twice the 32 GB/s that the RTX 4090 achieves on PCIe 4.0 x16. Our testing revealed a potential performance impact of up to 25% when utilizing limited PCIe bandwidth. Puget Systems today put this interface to the test, confirming real‑world impacts on video editing workflows when lanes or generations are constrained.
In DaVinci Resolve benchmarks, Puget Systems found that configurations running at PCIe 5.0 x16, PCIe 5.0 x8, or PCIe 4.0 x16 yielded virtually identical render times. Dropping to PCIe 5.0 x4, PCIe 4.0 x8, or PCIe 3.0 x16 introduced a modest 10% slowdown. Further reducing bandwidth to PCIe 4.0 x4 or PCIe 3.0 x8 resulted in an increase of roughly 25% in render times. After Effects exhibited only minor slowdowns once the bandwidth dropped below 8 GB/s. Unreal Engine 5.5 virtual production tests recorded about a 7% drop in average frame rates at the lowest lane counts. By contrast, Blender offline renders and OctaneBench scores remained essentially unchanged, and Llama LLM benchmarks showed no measurable dependency on PCIe speed.
The PCIe 5.0 on RTX 5090 employs the same NRZ signaling as PCIe 4.0 but incorporates stricter signal integrity measures, including decision feedback equalization and tighter timing controls. Although fully backward compatible with PCIe 4.0, 3.0, and even older standards, the RTX 5090's massive bandwidth headroom raises the question of how much performance is lost on legacy slots or when lanes are shared with NVMe drives. These findings reveal a common limitation of modern motherboards: most reserve full x16 lanes for a single slot, forcing any additional devices or drives to operate at half or quarter speed. As a result, a flagship GPU can unknowingly operate at PCIe 4.0 x4, extending project turnaround times for professionals working with high-resolution timelines or complex 3D scenes. For studios and power users planning multi-card configurations, the clear recommendation is to verify that the RTX 5090 remains in a full-bandwidth slot.
Sources:
Puget Systems, via Tom's Hardware
In DaVinci Resolve benchmarks, Puget Systems found that configurations running at PCIe 5.0 x16, PCIe 5.0 x8, or PCIe 4.0 x16 yielded virtually identical render times. Dropping to PCIe 5.0 x4, PCIe 4.0 x8, or PCIe 3.0 x16 introduced a modest 10% slowdown. Further reducing bandwidth to PCIe 4.0 x4 or PCIe 3.0 x8 resulted in an increase of roughly 25% in render times. After Effects exhibited only minor slowdowns once the bandwidth dropped below 8 GB/s. Unreal Engine 5.5 virtual production tests recorded about a 7% drop in average frame rates at the lowest lane counts. By contrast, Blender offline renders and OctaneBench scores remained essentially unchanged, and Llama LLM benchmarks showed no measurable dependency on PCIe speed.
29 Comments on PCIe Bottlenecks Slash NVIDIA GeForce RTX 5090 Content Creation Performance by 25%
Actual title should be like this :
Performance of RTX 5090 drops by up to *25% !
(*when you run it at PCIe 4.0 x4, PCIe 3.0 x8 or PCIe 2.0 x16)
that news piece shows pcie 4.0 x 16 electrical lanes is still enough. Overspending on a pcie 5.0 mainboard may not be wise when building on a restricted budget.
In my point of view pcie 5.0 is a hoax. pcie 5.0 NVME are barely faster as my KC3000 2TB @ pcie 4.0. It seems this is the same for graphic cards.
AMD B450, afaik am4 chipset, mainboards or similar dated hardware slowly get issues with new graphic cards. AFAIK PCIE 3.0 on the graphic card slot.
Besides, I can guarantee you there are lots of 5090 buyers who went into debt to buy the thing. Those types of luxury items tend to draw in people who really cant afford them in the first place (see also: nice cars, expensive houses, "luxury" vacation packages, "luxury" clothing, ece).Before PCIe, the bottleneck on AM4 will be the CPU. Sure they're fine, but there's a reason they use the 9800x3d to test games on the 5090. On AM4, your limit is the 5800x3d, which is roughly the same as a 7800. That will become a "restriction" before the PCIe bus will.
PCIe is a far worse issue on low VRAM cards, like the 8GB abominations we've been getting, once stuff has to be swapped to system RAM performance tanks. Even 5.0x4 is vulnerable to this.
The FEs are 2899 but impossible to get (best buy exclusive) seems most things in canada are now available at MSRP. I wanted a FE but settled for a TUF OC, didn't want the gigabyte cards for their leakage.
And here my OCD was going wild think 5.0 8x would make a difference when I install a second gen 5 ssd. Good to know it wont
That's why 4GB, and now 8GB, cards show significant performance regression on cut down busses compared to larger VRAM cards, because they have to swap out stuff with system RAM and saturate that PCIe bus whenever they do so.
It would seem that this is little more than a make work test done by someone with nothing better to do but who doesn't want to pick up a broom and sweep the floor
I mean it was like, you buy a xx90 class card and people act like its a sports car or something. I understand the 5090 is more expensive still but I don't think the disconnect has changed. Just because you bought a 5090, doesn't mean you have to go buying motherboards with features you don't need.
There's people who can just barely scrape up the money to buy one, and there's people where its nothing but a rounding error on their bank account. Not the same thing.
My hobby before I got back into computers, ancient coin collecting was totally ruining me financially (well kinda, I mean I still have them, so I could sell them if I wanted, potentially even for more than I bought them for, but I don't wanna....), anyway I got back into PCs because I needed something cheaper to occupy my time. And cheaper it certainly is.
PC building is cheaper than a lot of hobbies, even taking the price of the 5090 into account.
The usual upgrade question was: Is it a CPU problem (limit) or a GPU problem (Iimit).
Just because a nvidia 5090 was used to determine the influence of the bus speed does not change the facts about the bus speed.
My comment was purely on the bus speed of the combination of a mainboards with a cpu.
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Do all tasks for a graphic card needs a ryzen 9800x3d or better processor with pcie 5.0 mainboard? Yes? I'm sorry i was so wrong.
e.g. I think those mining mainboards only had a single pice lanes each. I never was in teh gpu mining thing.
Also.... this headline is kinda clickbaity.
this type of crap is fun when someone puts a 5090 on a 10 year old optiplex for the laughs.