PCIe 4.0 and PCIe 3.0 – Difference between x8 and x16 with the fastest cards – Where does the bottleneck begin?

1 - Einführung und Messaufbau 2 - Benchmarks: 1280 x 720 Pixels 3 - Benchmarks: 1920 x 1080 Pixels 4 - Benchmarks: 2560 x 1440 Pixels 5 - Benchmarks: 3840 x 2160 Pixels 6 - Benchmarks: 3840 x 2160 Pixels, Full AAA 7 - Gegenüberstellung, Zusammenfassung und Fazit

With only 1.56% performance loss, the disadvantage compared to PCIe 3.0 @8 is hardly visible with this fast card and you almost reach the range of possible measurement tolerances. This is still measurable, but no longer subjectively perceptible compared to the run with @16. The difference in both PCIe 4.0 measurements with the Radeon RX 5700XT, however, is again significantly below one percent, which one has to impose as a measurement tolerance, at 0.3%. The more than 13 FPS advantage of the Quadro RTX 6000 @8 compared to the RX 5700 XT shows again that the interface is obviously not very important when the graphics card is fully loaded.

You can see the difference quite well again on the FPS curves:

Now let’s take a look at the percentiles, because the 99th percentile is the most important one. Percentile isn’t everything. What you see is flattening of the curves overall, which, with one exception, is no longer as strong as before.

In terms of frame time, both runs with the Quadro RTX 6000 are in front, the full run before the halved bus variant. The RX 5700XT performs approximately the same with both connections. Also here I have the whole progressions later as single graphics for each map.

The evaluated variances can then again illustrate this a little more precisely, because the Quadros are again the measure of all things. The two measurements on the PCIe 4.0 are virtually identical.

Individual graphics for each run as picture gallery

Assassin's Creed Odyssey - Quadro RTX 6000 @8 - FrameTimeSolo - 3840 x 2160 Pixels Extreme High Settings, no AA

Assassin's Creed Odyssey - Quadro RTX 6000 @16 - FrameTimeSolo - 3840 x 2160 Pixels Extreme High Settings, no AA

Assassin's Creed Odyssey - Sapphire RX 5700 XT Nitro+ 8GB @8 - FrameTimeSolo - 3840 x 2160 Pixels Extreme High Settings, no AA

Assassin's Creed Odyssey - Sapphire RX 5700 XT Nitro+ 8GB @16 - FrameTimeSolo - 3840 x 2160 Pixels Extreme High Settings, no AA

Assassin's Creed Odyssey - Quadro RTX 6000 @8 - FPSvsFrameTimeDiff - 3840 x 2160 Pixels Extreme High Settings, no AA

Assassin's Creed Odyssey - Quadro RTX 6000 @16 - FPSvsFrameTimeDiff - 3840 x 2160 Pixels Extreme High Settings, no AA

Assassin's Creed Odyssey - Sapphire RX 5700 XT Nitro+ 8GB @8 - FPSvsFrameTimeDiff - 3840 x 2160 Pixels Extreme High Settings, no AA

Assassin's Creed Odyssey - Sapphire RX 5700 XT Nitro+ 8GB @16 - FPSvsFrameTimeDiff - 3840 x 2160 Pixels Extreme High Settings, no AA

Assassin's Creed Odyssey - Quadro RTX 6000 @8 - Unevenness - 3840 x 2160 Pixels Extreme High Settings, no AA

Assassin's Creed Odyssey - Quadro RTX 6000 @16 - Unevenness - 3840 x 2160 Pixels Extreme High Settings, no AA

Assassin's Creed Odyssey - Sapphire RX 5700 XT Nitro+ 8GB @8 - Unevenness - 3840 x 2160 Pixels Extreme High Settings, no AA

Assassin's Creed Odyssey - Sapphire RX 5700 XT Nitro+ 8GB @16 - Unevenness - 3840 x 2160 Pixels Extreme High Settings, no AA