How well does the RTX 5090 perform when it’s not connected via PCIe 5.0 x16? Initial benchmarks make it clear that you’ll experience little loss.
At the beginning of the month, Nvidia presented the RTX 5090 and its little siblings, the first graphics cards to be connected via PCI Express 5.0.
However, not all mainboards on the market have this standard – instead, you may need to connect your new GPU to a PCI 4.0 slot. Logically, this raises the question of whether you will experience a performance penalty as a result.
This question is the portal in an extensive test and examined the RTX 5090 in different configurations. The Nvidia GPU was tested for possible performance losses from the full bandwidth with PCIe 5.0 x16 to PCIe 3.0 x8.
RTX 5090 with PCI-Express 4.0: Hardly any noticeable performance loss
To summarize TechPowerUp’s conclusion: you shouldn’t notice any huge differences if your new Blackwell graphics card can “only” work with PCI-Express 4.0 or 3.0.
The RTX 5090 was tested in a system with an AMD Ryzen 7 9800X3D on a current X870E motherboard and 32 GB of RAM to exclude possible other bottlenecks.
- The average performance loss when switching from PCIe 5.0 x16 to PCIe 4.0 x16 is about one percent. These values apply regardless of the resolution and could be determined in Full HD as well as 1440p and 4K.
- You lose a little more performance if you have to make do with PCIe 3.0 x16 or PCIe 4.0 x8. Here, a minus of around four percent can be observed.
- Logically, PCI 3.0 x8 performs the worst: Depending on the resolution and game, you will “lose” around 10 percent of performance.
In general, the results should not come as a surprise: the available bandwidth is only a limiting factor in highly demanding situations that occur rarely.
With the RTX 5090, for example, a noticeable difference would be noticeableif a game or application wanted to use more than the 32 GB GDDR7 video memory.
In the previous generation, a performance loss of around ten percent was observed when the RTX-4000 graphics card was confronted with memory-guzzling RAW media processing; and even here, only when it was pushed to its limit via PCIe 4.0 x4 / PCIe 3.0 x8 (via PugetSystems ).
Second benchmark comes to the same conclusion
Also the…Tech YouTuber Hardware Canucks..has taken a closer look at the PCIe scaling of the RTX 5090 and unsurprisingly comes to the same conclusion.
- In a pure rasterizing scale, the YouTuber also comes to the conclusion that the loss of performance with the nominal downgrade from PCIe 5.0 x16 to PCI-Express 4.0 x16 is kept within limits at around one percent.
- When it comes to ray tracing performance, on the other hand, you’ll have to live with a maximum loss of three percent if you play in 4K resolution.
