OCuLink outpaces Thunderbolt 5 in Nvidia RTX 5070 Ti exams — latter as much as 14% slower on common in gaming benchmarks

External graphics enclosures have develop into a preferred approach to improve the gaming or computing efficiency of thin-and-light laptops and small-form-factor desktops. However, a vital query is which interconnection expertise is the most effective match when it comes to efficiency, as there are a number of eGFX choices out there with Thunderbolt 3/4, Thunderbolt 5, and OCuLink connectors. Try Some Tech has examined all of them and got here to a considerably anticipated conclusion: pure PCIe 4.0 connectivity makes extra sense. However, Thunderbolt 4 and 5 are extra widespread.

OCuLink vs Thunderbolt 5: What is what

OCuLink (Optical-Copper Link) is a high-speed cable interface standardized by PCI-SIG to provide a direct PCIe connection between devices, generally SSDs, but more recently GPUs. Unlike Thunderbolt or USB, OCuLink avoids protocol tunneling, delivering lower latency and higher efficiency as it is essentially a native PCIe link. It supports PCIe 3.0 or 4.0 with up to four lanes, enabling bandwidth of 32 GT/s to 64 GT/s. However, while it is highly effective in terms of raw performance, OCuLink lacks mainstream adoption, is not hot-swappable, and does not support features such as power delivery, USB, or video output, which is why it is hardly used in consumer laptops. It can be used both inside and outside of desktop workstations.

Thunderbolt 4 and Thunderbolt 5 were developed by Apple and Intel for consumer devices, offering versatile, multi-protocol interfaces that utilize the USB-C connector to combine PCIe, USB, and DisplayPort functionality. Thunderbolt 4 supports PCIe 3.0 x4, offering up to 32 GT/s for data transfer. Thunderbolt 5 upgrades this to PCIe 4.0 x4, doubling the bandwidth to 64 GT/s and introducing advanced features such as 240 W charging and up to 120 GT/s for high-end displays. While both offer plug-and-play convenience, charging, and display support, they add latency due to protocol overhead. Thunderbolt 5 significantly narrows the performance gap with OCuLink, making it more viable for eGPUs, but let us check the actual results.

The Results

When it involves uncooked bandwidth, an OCuLink connection achieved a throughput of round 6.6 GB/s host-to-device and 6.7 GB/s device-to-host, considerably outpacing TB5, which achieved a throughput of 5.6 GB/s host-to-device and 5.8 GB/s device-to-host. This is a notable distinction, and it will likely be essential relating to storage and data-intensive workflows. But what about gaming?

A GeForce RTX 5070 Ti graphics card directly connected to an Intel Core Ultra 7 265K outperforms the same card connected using OCuLink and TB5. When it comes to external connections, across 12 tested games, Thunderbolt 5 consistently trails behind both OCuLink in average FPS.

Compared to OCuLink, TB5 delivers roughly 13%–14% lower performance on average, with heavier losses in demanding titles such as Spider-Man: Miles Morales (-20%) and Red Dead Redemption 2 (–23%). Against native PC connections, TB5 lags by 19%–25%, peaking at a 36% drop in Spider-Man: Miles Morales. The only exception is Ghost of Tsushima, where all three configurations reached 120 FPS, suggesting a CPU performance ceiling rather than an interface limitation. Overall, TB5 improves on TB4 but still lags behind OCuLink due to protocol overheads.

However, how useful is OCuLink for an average person? OCuLink is a specialized connector, not used on consumer devices. Due to a lack of compatible laptops, Try Some Tech conducted tests using a desktop system built around an Intel Core Ultra 7 265K CPU, an Nvidia GeForce RTX 5070 Ti graphics card, and a motherboard featuring two Thunderbolt 5 ports. The eGPU enclosure selected was the PELADN Link S-3, which offered a variety of ports, including dual Thunderbolt 5 ports, although it did not come with a proper cable. For OCuLink, Try Some Tech used an industry-standard cable and an external GPU.

Summary

While Thunderbolt 5 brings meaningful improvements over its predecessor, it is yet to be widely supported on modern devices. Also, it still falls short of the raw performance offered by OCuLink due to protocol overhead. OCuLink delivers superior bandwidth and lower latency, making it the optimal choice for achieving maximum eGPU performance. However, its limited adoption and lack of consumer-friendly features keep it out of reach for most users. Ultimately, Thunderbolt 4 and 5 remain the practical choices, while OCuLink is the performance leader for those who can make it work.

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