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.