While your average mini PC is anything but a gaming beast, you can transform it into a decently beefy gaming rig by connecting an external GPU (eGPU). While Thunderbolt and USB4 are the most popular ways to do this, you can get much better performance if the mini PC in question features an OCuLink port, even compared to the latest and greatest Thunderbolt version, Thunderbolt 5 .
What is OCuLink?
And why it's better than Thunderbolt
OCuLink (Optical-Copper Link) is a connection standard that taps directly into a computer's PCIe lanes. It lets you connect any external PCIe device to a PC with an OCuLink port via a cable, much like you would with a Thunderbolt port.
Unlike Thunderbolt, OCuLink uses a dedicated connector instead of USB-C . It also doesn't provide power to connected devices, and you need to power off the PC before connecting or disconnecting devices. Thunderbolt, on the other hand, supports both power delivery and hot-plugging.
Another key difference is that OCuLink offers a near-direct connection to a computer's PCIe lanes, resulting in very low latency and higher effective bandwidth. Thunderbolt also carries a PCIe signal, but it relies on additional controllers between the CPU and the external device (such as an eGPU). That extra layer introduces latency and overhead, reducing real-world performance compared to its theoretical limits.
Compared to Thunderbolt 4, which tops out at 32Gbps of PCIe bandwidth, OCuLink uses a PCIe 4.0 x4 link and can provide up to 64Gbps, effectively doubling Thunderbolt 4's PCIe throughput. When we account for Thunderbolt overhead, that difference grows even larger.
Thunderbolt Technology
Another thing OCuLink has going for it is that it's an open standard, unlike Thunderbolt, which requires manufacturers to shell out cash for licensing fees if they want to equip their machines with Thunderbolt connectivity. That said, USB4, another open standard, works similarly to Thunderbolt 4 with PCIe devices like eGPUs, so you can use USB4 instead of Thunderbolt in much the same way. Even so, OCuLink delivers much higher performance than both Thunderbolt 4 and USB4.
When pitted against one another, OCuLink proves to be a much better solution for eGPUs. Our friends at XDA Developers ran some tests comparing USB4 and OCuLink. The results show that while performance can be similar in some games ( Shadow of the Tomb Raider ), OCuLink can be up to three times faster in other titles tested, which is impressive.
The reason for such a huge disparity is that real-life Thunderbolt/USB4 bandwidth is much lower than advertised due to overhead. As you can see in the video below, courtesy of the Try Some Tech YouTube channel, Thunderbolt 4 caps out at just 23Gbps, while OCuLink provides around 63Gbps of bandwidth, which is only 1Gbps below its theoretical maximum throughput. On the other hand, Thunderbolt's theoretical speed is 32Gbps, meaning it leaves a lot of bandwidth (and performance) on the table.
OCuLink is faster than even Thunderbolt 5, which provides up to 64Gbps of PCIe bandwidth, matching OCuLink, at least on paper. In reality, though, OCuLink comes out on top again. Try Some Tech compared Thunderbolt 5 and OCuLink, and the results speak for themselves.
Despite matching OCuLink on paper, an eGPU connected via Thunderbolt 5 was, on average, ~20% slower than when connected via OCuLink, with worst-case performance nearly 40% slower. Better still, the GPU used for testing (an RTX 5070 Ti) was only about 10% slower via OCuLink than when directly connected to a desktop PC via a full-fledged x16 PCIe 5.0 port.
A good number of mini PCs feature an OCuLink port
A perfect mini PC companion
Bill Loguidice / How-To Geek
While you won't find a Windows mini PC with Thunderbolt 5 connectivity (the only mini PC with Thunderbolt 5 as of this writing is the M4 Pro version of the Mac mini), there are plenty of mini PCs featuring OCuLink.
In other words, as long as it supports OCuLink and has a decent CPU, you can turn any mini PC into a gaming beast. All you need is either an OCuLink eGPU enclosure or an eGPU with native OCuLink support. If you opt for an enclosure, you'll also need a PSU.
If you already own a mini PC with an OCuLink port, I recommend getting the AOOSTAR AG01 eGPU enclosure. It comes with an OCuLink port and a built-in 800W PSU, which is more than enough even for GPUs like the RTX 5090. If you already have a power supply, check out the MINISFORUM DEG1 enclosure—it's more affordable but requires a PSU.
I'd also recommend using at least a PCIe 4.0 GPU. GPUs limited to PCIe 3.0 will effectively cap out at around 32Gbps over OCuLink, while PCIe 4.0 (and newer) GPUs can take full advantage of the 64Gbps bandwidth.
If you're looking to buy a mini PC with OCuLink and turn it into a compact gaming machine, check out the AOOSTAR MACO. The version with 24GB RAM but without an SSD goes for around $329 as of this writing, but you can also get a variant with a 1TB SSD for $459. The machine is powered by an AMD Ryzen 7 PRO 6850H, a capable 8-core CPU that should work great with any desktop GPU, though it may bottleneck high-end options such as the RTX 4090, RTX 5090, RTX 5070 Ti, or the RX 9070 XT.
OCuLink is the best way to use eGPUs, and it's not changing anytime soon
Before Thunderbolt 5 arrived, OCuLink was easily the better eGPU solution, especially for mini PCs, where it's actually available on many models. And even after Thunderbolt 5, not much has changed. OCuLink is still the superior eGPU connection, and the best option if you'd like to build a mini PC-based, ultra-compact gaming setup.
