Resizable Base Address Register. In short, rather than the 256MB of mapped memory available to the CPU for any PCI device, ReBAR capable devices can map larger memory to the CPU’s addressable memory space. Without ReBAR or sufficient tricks (that Intel GPUs lack) you have to shuffle 256MB chunks around between GPU and CPU.

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bpye 14 hours ago | parent [-]

> sufficient tricks (that Intel GPUs lack)

Isn't it just being able to shift the window of GPU memory visible to the CPU?

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p_l 3 hours ago | parent [-]

Yes, intel lacks a remapping mechanism to support BAR smaller than the total VRAM size.

	▲	wtallis 7 minutes ago \| parent [-]
		Using an Intel discrete GPU on a system that lacks ReBAR support results in somewhat lower performance, not a complete inability to use more than 256MB of VRAM.