[TheFlash]

There is no such thing as direct rendering, commands are always buffered by the driver before being sent to the gpu. (and Forward rendering as in the rendering technique ?)

With Vulkan/Dx12 you can record multiple command buffers in parallel. That is not possible in OpenGl/Dx11 (There are 'deferred contexts' that let you do things in parallel but it's really not great).

By 'multiple cores on the GPU', I think you mean the hardware queues ? Usually there are 3 (on PCIe discrete GPUs, that is) a graphics queue to record any commands, a compute queue for compute tasks, and a copy queue for DMA copies across the PCIe bus. I don't know if you can access them independently on older APIs, but on Vulkan/dx12 you certainly can.