The SGI Visual Workstation was a series workstation computers manufactured by Silicon Graphics, Inc. designed to run Windows NT, Windows 2000 and Linux. The Visual Workstations are notable for their use of Intel Pentium II and Pentium III processors (rather than the 64-bit MIPS RISC architecture usually used in SGI computer products). The 320 and 540 models were notable for their departure from the standard IBM AT-derived architecture which the great majority of Intel 386-based computers use. For example, unlike virtually all other Pentium-class systems, these two Visual Workstations did not include a BIOS (often criticized as hackish and obsolete), in favor of a port of the same powerful ARCS firmware system used in all other contemporary SGI workstations.
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There were really two series of the Visual Workstations. All were based on Intel processors; the first series (320 and 540) used SGI's ARCloader PROM and Cobalt video chipset, the remainder were essentially standard PC's.
The 320 and 540 used a Unified Memory Architecture (UMA) memory system. This shared the video and system memory and ran them at the same speed, and allowed for up to 80 percent of the system ram to be applied to video memory. The allocation was static, however, and was adjusted via a profile. The 320 and 540 also used the on board Cobalt video adapter, which was SGI's proprietary graphics chipset. The firmware the systems used was a PROM that enabled booting into a graphical subsystem before the OS was loaded. In this regard they resembled the Irix/MIPS line of SGI computers such as the SGI O2.
The 320 and 540 also stood out for having Firewire (IEEE 1394) ports, on board composite/s-video capture, and USB keyboards and mice. They differed from each other in the 320 was dual Pentium II/III capable with 1GB maximum system RAM, while the 540 was quad Pentium III Xeon capable with 2GB maximum system RAM. Both computers used a proprietary DIMM module that was essentially the same as ECC SDRAM PC-100, but in a package one half normal size. The maximum memory per module was 96MB, and the SGI 320 had twelve memory slots. It is important to note that the Firewire ports that were built into the 320 never functioned. SGI distributed Orange Micro Firewire cards about a year after production started in lieu of fixing the Firewire ports.
Both the 320 and 540 were further limited by having PCI slots (albeit two 66 MHz and one 33 MHz slot) that operated at 3.3V, out of step with the 5v slots used by most manufacturers at the time. This limited the number of accessories that could be added.
The other Visual Workstations were built to compete with the new Intel processor based workstations that were considerably cheaper than SGI's line of MIPS workstations. They were little more than standard PCs, and used many parts that were also available in the aftermarket. They were criticized for using very cheap components, such as motherboards based on the VIA Apollo chipset for the SGI 230.
At the time it used the via apollo PRO 133A chipset which along with a CPU that had an FSB of 133Mhz and Ram that also ran at 133, made for a system that could deliver data incredibly fast. The key part of the workstation was the I/O you could send your data to a render station very quickly, with no bottlenecks.
The 320 and 540 Visual Workstations shipped originally with Microsoft Windows NT 4.0. Due to the ARCloader PROM, a custom Hardware Abstraction Layer (HAL) for Windows was necessary. Windows 2000 was the last release which included the required SGI-specific HAL. Because of that, and because SGI ceased supporting the Visual Workstation series, installation of future Windows versions such as XP is unsupported.
The 230, 330, and 550 also supported Windows NT and 2000. In addition, SGI offered these systems preconfigured with release 6.2 of the Red Hat Linux distribution. These systems have the letter "L" appended to their model numbers.
Because of the various SGI enhancements, in particular for the 320 and 540, Visual Workstations often out-performed Intel PCs of similar configuration in graphically-intensive or memory bound applications. However due to the hefty upgrade costs for the non-standard components it was more cost effective to purchase an entire new higher-specced non-SGI PC rather than purchase upgrades to a Visual Workstation.
All the Visual Workstations supported conventional CRT monitors and had VGA display connectors. As the 230 330, and 550 models used Nvidia Quadro cards they also supported DVI. The SGI 320 and 540 models shipped with the groundbreaking and stylistically matched 1600SW LCD display, using an OpenLDI display connector that required an accessory flat panel adapter. The SGI O2 also supported the 1600SW with an adapter.
The model numbers of the Visual Workstations:
Visual Workstations were initially equipped with either a single Pentium II or Pentium III processor or dual (SMP) Pentium III processors. The 540 and 550 models supported the Xeon implementation of the Pentium series, and could support up to four Xeons in an SMP configuration (only two for the 550). Although no SGI Visual Workstation was ever released with a CPU running higher than 700 MHz, some hobbyists have been able to run faster processors.
For the SGI 320 the limit is dual 1 GHz Pentium III processors or a single 1.4 GHz celeron.
Dual 1 GHz processors required a specific model of CPU, which was intended for Intel servers. Further, the voltage regulator, PROM, and revision of the motherboard also have to be correct for the setup to work.
With single processors the Powerleap Pl-iP3T "slocket" adapter and a Tualatin 1.4 GHz celeron processor is the limit, and is a straight bolt in installation. The Tualatin core gives a more modern processor, and the Powerleap adapter handles the voltage regulation to the CPU.
The SGI 540 has been reported to handle up to 900 MHz quad Xeon processors. These are the fastest Pentium 3 Xeons with the 100 MHz front side bus speed of the 540.
The 230, 330, and 550 models were essentially standard PCs and had the same capabilities and upgrade limits as other PCs of the time. The 230 and 330 were based on VIA chipsets, used socket 370 processors, and conventional SDRAM. The 550 used Slot 2 Xeon processors, the Intel 840 chipset, and RDRAM.
These three models had a generic PC BIOS, generic PC memory, and other non-differentiated parts. The video cards these systems used were Nvidia AGP cards based on the Quadro 2 chipset, and differed from aftermarket Quadros in their drivers.