The 8·24 does support resolutions higher than 640x480... up to 1152x870 (8-bit) but not multiscan monitors -- you have to set a fixed resolution on the adapter It supports the Portrait Display, too (640x870)

Unlike the (otherwise similar) Quadra 700 built-in video, there's no support for "modern" resolutions like 1024x768, either. But you can get 24-bit video at 640x480 with 1 MB VRAM; with that amount, the Q700 gets millions of colours only on 512x384 -- because it's doing 32-bit internally, for performance reasons.