eGPU gaming: Ice Lake-U processors offer nearly 50% better performance in some games than Comet Lake-H processors do
Choosing the right graphics card for an eGPU can be complex, but Jarrod's Tech has established an important performance bottleneck between some laptops. Often, laptop CPUs are spoken of as holding back the performance of desktop GPUs, but it is slightly more complicated than that. In a recent video, Jarrod's Tech compared a Dell G7 with a Razer Blade Stealth, which are configured with a Core i7-10750H and a Core i7-1065G7, respectively. On paper, the Comet Lake-H in the Dell G7 outperforms the Core i7-1065G7 in the Razer Blade Stealth in almost every performance metric. Not only does the Comet Lake-H chip have more cores than the Ice Lake-U one, but also clocks higher and has a much higher TDP. Jarrod's Tech has demonstrated that the Core i7-10750H bottlenecks an eGPU more than the Core i7-1065G7 does, though.
Undoubtedly, the nature of pairing a laptop CPU with a desktop GPU in an eGPU setup hinders gaming performance, somewhat. However, it turns out that the implementation of Thunderbolt 3 is a greater bottleneck than core count or clock speeds. Intel integrated the Thunderbolt 3 controller on the SoC with Ice Lake, but kept it separate on Comet Lake-H. Integrating the controller reduces latency, which often translates to huge in-game framerate performance improvements.
This different Thunderbolt 3 controller design allows the Core i7-1065G7 to average over 20% higher framerates than the Core i7-10750H at 1080p, although this varies between 2% and 48% depending on the game. There are hardly any differences between the two chips in Control, but the Core i7-1065G7 dominates the Core i7-10750H in titles like Metro Exodus and The Witcher 3. The difference between the two chips is slightly lower at 1440p and 4K, but there is still a huge performance gulf in most games.
Overall, it seems that an Ice Lake-U machine would be a better option for eGPU gaming than a laptop with a Comet Lake-H processor. We imagine that this will change when Intel finally switches to 10 nm H-series processors, but that may not be for a while yet.