Who actually makes the OEM GPUs?

[MotorMouth]

If you buy a prebuilt from Dell or HP or whomever, it'll come with a really cheaply built GPU with the same branding as the rest of the system.

However, most of those companies are not listed as board partners for either AMD or Nvidia. So, it seems like those must be getting manufactured by MSI, PNY, or one of the existing AIB partners and rebranded.

Who, in general, makes those GPUs?

[GuiltySpark_]

One, they’re not always cheaply made. They’re plain sometimes but don’t mistake that for poor quality. 
 

Secondly, OEM GPUs are usually just made by the same AIB board partners that make all GPUs at least in my experience. 
 

 

[Bobbysixjp]

OEM GPUs are usually made by the same companies that make other models of GPUs. For example, Zotac make OEM GPUs as well as the more 'premium' models. But they are only available with pre-builts and not sold elsewhere. My first (and only) pre-built came with a ZOTAC OEM 1060 3GB. They do tend to be more cheaply made with just a basic cooler bolted on and no RGB. Even now in 2021 some pre-builts still have blower style GPUs - not necessarily bad but not the best either.