Depends on the desktop. I have a NanoPC T4, originally as a set top box (that’s what the RK3399 was designed for, has a beast of a VPU) now on light server and wlan AP duty, and it’s plenty fast enough for a browser and office. Provided you give it an SSD, that is.
Speaking of Desktop though the graphics driver situation is atrocious. There’s been movement since I last had a monitor hooked up to it but let’s just say the linux blob that came with it could do gles2, while the android driver does vulkan. Presumably because ARM wants Rockchip to pay per fucking feature per OS for Mali drivers.
Oh the VPU that I mentioned? As said, a beast, decodes 4k h264 at 60Hz, very good driver support, well-documented instruction set, mpv supports it out of the box, but because the Mali drivers are shit you only get an overlay, no window system integration because it can’t paint to gles2 textures. Throwback to the 90s.
Sidenote some madlads got a dedicated GPU running on the thing. M.2 to PCIe adapter, and presumably a lot of duct tape code.