offerings were in production until the STB-3dfx merger. The series was highly successful as the Voodoo Graphics and Voodoo2 chipsets introduced consumer-grade 3D graphics into the PC and arcade markets, whereas such capabilities had previously been present primarily in very high-end CAD and graphic design workstations. A critically acclaimed feature of the Monster 3D II (and all other Voodoo2 boards) was the capability to connect two identical boards in a SLI (Scan-line Interleave) configuration. In SLI, a pair of Voodoo2 boards splits the effort of rendering the 3D scene between alternating raster lines, allowing performance to be nearly doubled. Listing of Monster 3D-branded boards Diamond Monster 3D 3dfx Voodoo1 4MB PCI Diamond Monster 3D II 3dfx Voodoo2 8MB PCI (4MB video RAM, 4MB texture RAM) Diamond Monster 3D II 3dfx Voodoo2 12MB PCI (4MB video RAM, 8MB texture RAM) Diamond Monster 3D II MEGAMonster bundle (Monster 3D II, MEGAMonster Voodoo2 companion board, MEGAMonster (SLI) cable) (a Voodoo2 SLI bundle offered by Diamond) Diamond Monster Fusion Z100 3dfx Banshee 16MB PCI/AGP (Referred to as the "Mon Fusion" by the sticker on many cards) Viper The Viper line was Diamond's high-end offering. Initially it consisted of a graphics accelerator board for VLB or PCI that was a combination of two graphics chips. For non-GUI environments such as DOS, the original Viper used an Oak Technology OTI-087 display chip with its own 256 KB DRAM. This chip was rather slow and basic. The Viper SE card moved to a Weitek 5186 chip with 1 MB DRAM for non-GUI functions. For GUI environments such as Windows, the Viper cards used a Weitek graphics co-processor which accelerated many drawing functions and performed very well for its time. The original Viper used the Weitek P9000/P9001, while the Viper SE used a Weitek P9100, both lines equipped with 2-4 MB VRAM. The separate slow DOS chip was a problem for owners who played DOS games because these chips were quite slow and had limited and buggy VESA BIOS Extensions implementations. While the GUI accelerator was very capable, drivers from Diamond were rather buggy and were only revised a few times during the lifetime of the card. Towards the end of the 1990s, the Viper line consisted of NVIDIA-based graphics cards. The Diamond Viper V330 used the highly integrated RIVA 128 accelerator that featured very capable 2D, 3D and video acceleration. The later Diamond Viper V550 and V770