Back in the DOS days of gaming (more specifically, 80286 - 80486 era), developers typically needed to choose between using the chunky and easier Mode 13h or the more complex "Mode X" that provided hardware scrolling and VGA memory-to-memory copies.
From what I understand, Mode 13h has a simple memory layout where all 320x200 pixels are arranged in a linear fashion. While this mode was simple, it had a smaller resolution than Mode X and was limited to 64K of VGA memory. Which means the CPU must copy new information over the slower external bus (such as ISA).
Mode X was more complicated because it used planar graphics (bitplanes). But it also supported a higher resolution of 320x240 pixels. Which are also square vs. the slightly "stretched" pixels of Mode 13h. Another advantage of Mode X was it supported hardware panning (scrolling) across the entire 256K of VGA memory.
So it seems to me that Mode X would always be the mode to use when you want fast scrolling games like Jazz Jackrabbit. Despite the more complex memory layout it seems to be a superior mode.
Then I recently read that the VLB (VESA Local Bus) eliminated much of the advantages of Mode X because it supports a direct connection to a 486 processor. While the CPU would have to drive more pixels for scrolling, a mid-range 486 could easily handle the task. Which means that using a simpler graphics mode such as Mode 13h would now be preferable because it could greatly increase development productivity.
So my two-part question becomes, is there ever a circumstance where Mode 13h is a better choice for fast scrolling DOS games over Mode X? Second, how (if at all) did the VLB standard affect this decision?