High-end Mini-PC test pairs 65W Ryzen 7 7840HS and external GeForce RTX 4090 GPU via OCulink, only 10% performance loss in 3DMark
The newest system by Minisforum and NVIDIA’s most powerful desktop GPU have been tested together by TechTablets.
The Minisforum EliteMini UM780 XTX is a new addition to the current high-end Mini-PC market. It’s already available for purchase, and it’s getting a lot of attention for two main reasons. First, it features a high 65/70W TDP configured for its AMD Phoenix-based system. Second, it also has an OCulink (Optical-Copper Link) connector.
OCulink marks a small revolution in the Mini-PC and handheld gaming space, addressing a significant limitation of Thunderbolt and USB4 connections for external GPUs—their restricted 40 Gbps bandwidth. In contrast, the OCulink connector provides 63 Gbps of bandwidth, something that cannot be ignored when discussing external GPUs.
UM780 XTX with OCulink cable, Source: TechTablets
Equipped with the AMD Phoenix APU, the UM780 XTX utilizes the Ryzen 7 7840HS processor with a default TDP of 65W and a max boost of 5.1 GHz. While it doesn’t feature the flagship Ryzen 9 7940HS APU from AMD, the UM780 XTX can offer a TDP up to 70W once configured. This option is listed in the BIOS as “Performance Mode” and it has to be enabled manually. For this testing, however TechTablets used the default setting of 65W, which is how the system is configured out of the box.
Worth noting that although the specifications for the upcoming desktop Ryzen 8000G APU series based on Phoenix die are currently unknown, it’s expected that those models will adhere to a default TDP of 65W. However, the UM780 XTX can exceed or at least match this limit.
Despite its advantages, the mobile APU has some drawbacks, including a limited number of available PCIe lanes. Despite the increased OCulink bandwidth, still relies on a PCIe connector, in this case M.2 PCIe Gen4x4 slot. Therefore, users must sacrifice one of the M.2 slots and use the supplied adapter (included with the device). Furthermore, users still need to purchase the cable, external GPU enclosure (or at least a dock), and power supply for the setup to function. That combined with RTX 4090 certainly won’t be a small investment, but in this case, this is all for science.
UM780 XTX OCulink adapter, Source: TechTablets
With this configuration, the card achieved a score of 32,459 points in 3DMark TimeSpy. While the average score for an RTX 4090 running in a standard desktop environment is 36,291, the configuration with the AMD Ryzen 7 7840HS only experiences a 10.5% performance loss in comparison. Typically, a 20% drop is observed with normal Thunderbolt/USB4 configurations, indicating that OCulink can indeed enhance performance. Despite this improvement, there’s still a bottleneck, as the GPU is limited to a PCIe Gen4x4 connection, and the mobile CPU will inevitably restrict the capabilities of a 450W GPU. Nevertheless, in this configuration, an external GPU begins to make sense.
Desktop RTX 4090 in TimeSpy connected via OCulink, Source: TechTablets
TechTablets compared the integrated graphics and external graphics, though it’s not an apples-to-apples comparison, making detailed analysis challenging. Nevertheless, it provides a glimpse of the potential performance boost achievable with NVIDIA’s RTX 4090 GPU with this Mini-PC. Take a look at the video if you’re interested in external GPUs and the emerging standard of OCulink.
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