cope well with the increase in front-side bus speed to 50 MHz. If one could achieve reliable operation of VLB at 50 MHz, it was faster but again, this was notoriously difficult to achieve, and often it was discovered not to be possible with a given hardware configuration.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. Difficulty of installation The length of the slot and number of pins makes VLB cards notoriously difficult to install and remove. The sheer mechanical effort required is stressful to both the card and the motherboard, and breakages are not uncommon. This is compounded by the extended length of the card logic board; often there is not enough room in the PC case to angle the card into the slot, requiring it to be pushed with great force straight down into the slot. To avoid excessive flexing of the motherboard during this action, the chassis and motherboard had to be designed with good, relatively closely spaced supports for the motherboard, which is not always the case, and the person inserting the board had to distribute the downward force evenly across its top edge.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. Legacy Despite these problems, the VESA Local Bus became very commonplace on later 486 motherboards, with a majority of later (post-1992) 486-based systems featuring a VESA Local Bus video card. 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. PCI finally displaced the VESA Local Bus (and also EISA) in the last years of the 486 market, with the last generation of 80486 motherboards featuring PCI slots instead of VLB-capable ISA slots. However, some manufacturers did develop and offer "VIP" (VLB/ISA/PCI) motherboards with all three slot types. Technical data See also Industry Standard Architecture (ISA) Extended Industry Standard Architecture (EISA) Micro Channel architecture (MCA) NuBus Peripheral Component Interconnect (PCI) Accelerated Graphics Port (AGP) PCI Express (PCIe) List of device bandwidths (A useful listing of device bandwidths that include VLB) References Motherboard expansion slot IBM PC compatibles Local Bus Computer-related introductions in 1992