If you’ve been thinking about installing an RTX 4090 in a shiny new external GPU box, you might want to reconsider. Jarrods Tech on YouTube just released new video Here’s what the RTX 4090 can do with an external Thunderbolt GPU dock. The results were incredibly bad. The dock slowed down his 4090’s gaming performance and most games could only use his 50% of its power at best.
For testing, Jarrod used two different laptops. A more powerful Aorus 17X gaming laptop with an Asus Zenbook 14 OLED with i7-1260P processor and a more capable Core i9-12900HX. Jarrod also put together his 7950X desktop test rig as a baseline and in an external GPU dock configuration he saw how much performance the 4090 holds up.
Unfortunately, Jarrod neglected to share details of the external GPU dock he’s using, only mentioning that it’s a Thunderbolt 3 dock. This is a good thing considering most GPU docks today use Thunderbolt 3. But Jarrod switched to his Corsair 850W power supply outside. His 650W unit built-in didn’t have enough of his 8-pin power connector for his quad 8-pin power adapter on the 4090, so I powered it for testing.
In testing, Jarrod found that every title he tested could barely use 50% of the RTX 4090’s GPU horsepower. god of war One of the best games tested showing a 35% drop in performance at 4K on the i7-1260P Zenbook compared to the desktop 4090 configuration.
But in the worst case scenario, the external 4090 was up to 82% slower than the desktop version. Watch Dogs Legion in 4K.
Worse, the difference in performance between both laptops was also significantly different across most titles. assassin’s creed valhallathe 12900HX gaming laptop was up to twice as fast as an ultrabook with a slower i7-1260P processor.
This game was arguably the worst offender, but many other titles have seen similar behavior. red dead redemption 2, call of duty warzone, Watch Dogs Legion and some more.
The behavior is very strange, especially when the 12900HX is a very fast part. Jarrod suspects his resizable BAR feature has something to do with it, but isn’t sure.
In either case, pairing the RTX 4090 with a modern Thunderbolt 3 GPU dock seems like a bad idea, resulting in very low utilization of the 4090. The Thunderbolt 3 GPU dock has 4090 even at 4K resolution.
We’ll have to wait for much more capable Thunderbolt 4 or (possibly even Thunderbolt 5) GPU docks before cards like the RTX 4090 make sense as an option for external gaming. However, as high-end GPUs are always getting better and more demanding on both the CPU and external interfaces, it is unclear if high-end GPUs will reach similar performance to traditional desktop setups. It’s clear that if you want the best possible gaming performance in the near future, you should choose either the best gaming PC or the best gaming laptop, not an external GPU.