External GPUs have advanced significantly during the past few years. This subject is less popular among avid gamers, as the majority of them are likely to use water-cooled desktop PCs or gaming laptops for optimal performance. The eGPUs are meant for casual gamers and users with lightweight laptops who occasionally wish to play higher-resolution games or utilise the computing capacity for more demanding tasks.
There are several ways to add an eGPU to such systems, including Express Cards, M.2, mini PCIe, and Thunderbolt. eGPU enthusiasts prefer the second latter because of its simplicity and quickness. In addition to pre-built eGPU enclosures with bespoke graphics cards, gamers may also build their own.
The topic-specific forums are flooded with mid-range eGPU configurations. This is mostly due to the fact that externally accessible GPUs will never operate similarly to ones that are installed directly. The most popular GPU enclosure is the Razer Core X, which employs a Thunderbolt 3 port. There are currently no Thunderbolt 4 enclosures on the market, but this update wouldn’t much enhance performance anyhow.
There are solutions for more sophisticated users, such as M.2 to PCIe Gen4 connections, that should improve performance, but these setups are not plug-and-play. Therefore, it is best to stay with higher mid-range GPUs or assume that the card would lose a quarter of its performance.
Recently, a user of the eGPU forums has successfully integrated a desktop RTX 4090 Founders Edition into an ASUS Zenbook 14X Space Edition. This lightweight laptop features a Core i9-12900H CPU and no specialised graphics processing unit. Nonetheless, this system enables Thunderbolt 3, making it an ideal match for the Razer Core X enclosure.
The RTX 40 series, particularly the flagship 4090 SKU, requires a minimum of three 8-pin power connections to meet the 450W TDP specification. This indicates that an update to the power supply was required.
As an external GPU, the RTX 4090 may lose 20% of its efficiency on average. This performance was achieved on a GPU that was overclocked (+249 MHz on GPU, +1500 MHz on RAM, and at 133% power limit). It is a significant performance loss, but one must consider that it is paired with a modest, non-gaming laptop.
The only issue with this specific configuration is the price. The GPU costs $1600 by itself, while the casing costs an additional $300. Therefore, it costs the same as a high-end gaming laptop.