OCulink slashes RTX 4090 GPU performance by almost a quarter — still compares favourably to Thunderbolt 3, USB4

OCulink claims to deliver a superior experience to USB4 and Thunderbolt 3 and 4, thanks to its bidirectional 32 Gbps (64 Gbps total) PCIe connection. Despite its advantages over Thunderbolt 4, OCulink appears to suffer similar — although far less pronounced — limitations to the latest-generation Thunderbolt connection, at least in benchmarks tested by Golden Pig Upgrade on Weibo.

The Chinese reviewer posted a brief summary of his findings, which reveal that the Nvidia GeForce RTX 4090 loses close to 23% of its GPU performance when running on OCulink and displaying the graphics on the laptop in question. The GPUs were each tested in the eGPU enclosure and in an unspecified desktop setup for the baseline performance comparison.

Oculink graphics dock performance run points:

To RTX 4070 Ti Super:

Time Spy graphics points
Desktop: 24613
Graphics dock (internal screen):22199
Performance loss: 9.8 percent

To RTX 4090:

Time Spy graphics points
Desktop: 36487
Graphics Dock (Internal Screen):28230
Performance loss: 22.6 percent
Graphics dock (external screen):30429
Performance loss: 16.6 percent

Time Spy Extreme graphics points
Desktop: 19930
Graphics Dock (Internal Screen):18902
Performance loss: 5.2 percent
Graphics dock (external screen):19925
Performance loss: 0

Unsurprisingly, lower-power graphics cards, like the Nvidia GeForce RTX 4070 Ti Super, suffer a lesser performance hit. Replacing the built-in laptop display with an external monitor and increasing the display resolution helped matters further, reducing the bottleneck on the RTX 4090 to zero in the Time Spy Extreme test.

It's worth mentioning that benchmark results are not always indicative of real-world gaming performance, but at least 3DMark produces both a graphics and CPU score to more or less isolate the performance variables. In Notebookcheck's recent review of the Gigabyte Aorus RTX 4090 Gaming Box, we found the Thunderbolt 3 connection on that device to cut performance by as much as 36%.

While OCulink certainly still results in a performance penalty, it seems to be less severe than the hit from Thunderbolt 3 and 4. These eGPU enclosures, like the liquid-cooled GIGABYTE AORUS RTX 3080 Gaming Box (curr. $1,670 on Amazon) are a neat way to expand the capabilities of a less powerful device, like a thin and light laptop or handheld gaming PC, like the Asus ROG Ally (curr. $599.99 at Best Buy).