The VLB bus, VESALocal Bus (VLB), is a PC bus developed by the Video Electronics Standards Association ( VESA) for connecting high- performance graphics cards; it is also referred to as a video local bus.
The VLB bus is a local bus concept and supports direct communication between the CPU and expansion cards. The bus operates at the clock rate of the central processing unit (CPU), which may be a maximum of 66 MHz if no slots are occupied. There are two versions with 32-bit bus width: VLB 1.0 with 40 MHz and a data transfer rate of 133 MB/s and VLB 2.0 with 50 MHz clock and 166 MB/s data transfer rate. The second version has not been realized in the market. There are expansion options for 64 bits and transfer rates of 276 MB/s. The VLB bus, which is to be regarded as a discontinued model, has 116 contacts as a combined VLB/ ISA slot, 98 of which conform to the ISA bus.
The VLB is not a replacement for the ISA bus but a supplement to it.