VLB provides a standardized fast path that add-in (video) card makers could tap for greatly accelerated memory-mapped I/O and DMA, while still using the familiar ISA bus to handle basic device duties such as interrupts and port-mapped I/O.

In the early 1990s, the I/O bandwidth of the prevailing ISA bus, 8.33 MB/s for standard 16 bit 8.33 MHz slots, had become a critical bottleneck to PC video and graphics performance.

While IBM did produce a viable successor to ISA with the Micro Channel Architecture offering a bandwidth of 66 MB/s, it failed in the market because hardware manufacturers did not want to pay steep licensing fees to use it.

Additionally, makers of MCA-compatible cards were subject to IBM's licensing fees, which combined with MCA's greater technical requirements and expense to implement.

If two devices overwrite the same memory location in a conflict, and the hard-disk controller relies on this location (the HDD controller often being the second conflicting device), there is the all-too-common[citation needed] possibility of massive data corruption.The 486DX-50's successor, the 486DX2-66, circumvents this problem by using a slower but more compatible bus speed (33 MHz) and a multiplier (×2) to derive the processor clock speed.Due to the length of a VLB slot and the difficult installation that results from its length, a slang alternative use of the acronym VLB is Very Long Bus.

VLB importantly offers a less costly high-speed interface for mainstream systems, as only by 1994 was PCI commonly available outside of the server market through the Pentium and Intel's chipsets.