PCI-e 3.0 x8 vs. x16 FPS Performance Let's just post all the charts first, then talk numbers – they're similar enough that this is the easiest way to read the data. Metro: Last Light
This was a very loosely conducted test as more of a curiosity. We briefly look at PCI-e 3.0 (Gen3) x16 vs x8 to determine how much impact the lanes have on a single-GPU card.
A number of years ago, we published the article "Impact of PCI-E Speed on Gaming Performance" investigating whether you would see a difference between a video card in a PCI-E 3.0 x8 slot versus one in a x16 slot.At the time, we found that even the fastest video card available had nearly identical performance whether it was running at x8 or x16.
The Difference Between PCIe x8 And x16. A motherboard doesn't always come with two fully-featured PCI Express x16 slots. Available PCI Express lanes are often distributed across two slots, meaning ...
PCIe 3.0 x8/x8 vs. x16/x16 on Titan Vs Moving on to the PCIe lane bandwidth testing, our charts now focus on x16 and x8 configurations, both overclocked to push the limits of the PCIe clock.
Firestrike Ultra PCIe 3.0 x16/x16 vs. x8/x8 with 2080 Ti For Firestrike Ultra, we observed an FPS difference of about 1% -- it was a 0.9% difference in GFX 1 and a 1.0% difference in GFX 2.
An X8 card in a computer that supports PCIe 3.0 can give performance that's almost identical to an X16 card using the PCIe 2 spec. There's a further complication, as well. To keep costs down, manufacturers might produce a motherboard with slots that are the full X16 in size and data path, but only operate them at the X8 speed.
For our test, we're looking at PCI-e Gen3 x8 vs. PCI-e Gen3 x16 performance. That means there's a 66.7% difference in bandwidth available between the two, or a 100% increase from x8 to x16.
Thus, a PCI Express 2.0 x16 slot offers a maximum theoretical bandwidth of 8 GiB/s, while a PCI Express 3.0 x16 slot reaches 16 GiB/s. Summary of PCI Express Interface Parameters. Base Clock Speed: PCIe 3.0 = 8.0GHz, PCIe 2.0 = 5.0GHz, PCIe 1.1 = 2.5GHz Data Rate: PCIe 3.0 = 1000MB/s, PCIe 2.0 = 500MB/s, PCIe 1.1 = 250MB/s
For example, a PCIe 3.0 x16 video card will give you the greatest performance, but only if your motherboard also supports PCIe 3.0 and has a free PCIe x16 slot. If your motherboard only supports PCIe 2.0, the card will only work up to that supported speed (e.g., 64 Gbit/s in the x16 slot).