Mobile RTX 4090 GPUs are being sold for desktops with cracked dies in China

A makeshift solution.

Mobile RTX 4090 - Image: Pro Hi-Tech
Mobile RTX 4090 - Image: Pro Hi-Tech

Mobile versions of RTX 4090 and RTX 4080 are being sold as discrete desktop models in China. This is already ill-advised because of inherent risks, but the GPUs themselves may be cracked and less functional. Now, while Team Green never intended to sell its laptop video cards for this use, that hasn’t stopped certain manufacturers from attempting to fill the gap in the market.

The appeal here does make some sense. Sellers can shift RTX 4090M and RTX 4080M cheaper than their full-fat counterparts, as they’re not technically equivalent to the best graphics cards they share their name with. The pesky ‘M’ at the end shows they’re essentially ripped from top-end gaming laptops and engineered into an x16 PCIe format. While these options remain popular in China, the quality of the builds and benchmarks have largely remained a mystery until now. That’s because Pro Hi-Tech, a Russian tech channel (via Videocardz), has tested them.

Pro Hi-Tech has tested RTX 4090M and RTX 4080M when made into desktop GPUs

Pro Hi-Tech purchased two of these Chinese cards and put them through their paces using Cyberpunk 2077 and Forspoken to showcase quite the difference. However, with cracked dies, these mobile GPUs were hardly up to their full potential. This happens because the laptop graphics processors are either taken from broken laptops or bought in bulk with faulty motherboards. As evidenced by the gaming benchmarks, these mobile cards are around 20% weaker than their desktop counterparts, with the RTX 4090M on par with the RTX 4070.

A further deep dive into the mobile hardware reveals that they were actually “QUAL SAMPLES” meaning they were never made into proper production units in the first place. They could’ve been rejected production samples that never made it to market or were defective on the assembly line; hence why they’re snapped up dirt cheap. Power usage remains lower than the desktop versions, which is expected, however, the trade-off here is compromised thermal performance and longevity.

While you could spend considerably less on a mobile RTX 4090 or RTX 4080 with respectable performance, we can’t recommend it. There’s no guarantee these GPUs will last more than a couple of weeks or months. What’s more, if they’re coming pre-damaged with high thermals, then that seals their fate even faster. We recommend buying through official sources, as these aren’t even cheap enough to be considered a curiosity purchase.

Aleksha McLoughlin is an incredibly experienced hardware editor and writer. She's previously been the Hardware Editor for TechRadar Gaming, GamesRadar, PC Guide, and VideoGamer. She's also contributed hardware reviews and coverage for Dexerto, PC Gamer, Android Central, and Expert Reviews.