Out in Front: November 9, 1995

The 64-bit Viper-UMA unified-memory-architecture (UMA) version of Opti’s Viper core-logic chip sets provides graphics and video peripherals with direct access to the 64-bit memory bus instead of the 32-bit-wide PCI bus. The three-chip set lowers costs by combining the video and graphics memory with the main memory. UMA permits the system to allocate the correct amount of DRAM the frame buffer requires, eliminating the need for a dedicated frame-buffer DRAM. This approach eliminates 1 to 2 Mbytes of DRAM. Opti based the chip set on the UMA standard, called VUMA, which the Video Electronics Standards Association plans to ratify soon; Opti acted as chair for the standards committee that defined VUMA.

The devices offer a peak memory bandwidth of 500 Mbytes/sec and support of extended-data-out (EDO), burst EDO, fast-page-mode, and synchronous DRAMs. The chip set increases the peak transfer rate of the PCI bus to 132 Mbytes/sec for X1-1-1 transfers and contains deep buffers for concurrent operation of the CPU, the PCI master, and the graphics controller. The Viper-UMA also integrates a bus-master IDE controller to eliminate ISA bus restrictions for disk controllers. The Viper-UMA is compatible with Pentium-class µPs, including the Advanced Micro Devices K5, the Cyrix 6x86, and the Intel P54C/P55C. Price for the Viper-UMA is $25 (10,000).
—by John Gallant

Opti Inc, Santa Clara, CA. (408) 980-8178.