DOS Days

Old PC Computing Resource

"STB Systems has a winner in its new STB PowerGraph 64 PCI graphics accelerator ($199), and the company's improved STB Vision software gives added value even to the older PowerGraph Pro PCI ($239). Both boards provide decent performance at a reasonable price, but the newer, less expensive PowerGraph 64 has better potential in the long term.

Both STB offerings are DRAM cards that make use of 64-bit graphics accelerators from S3 Corp., but the PowerGraph 64 is particularly intriguing because it is the first shipping product to use the new S3 Trio64 integrated graphics accelerator chip. Based on the S3 Vision864 chip that drives the PowerGraph Pro, the Trio64 provides hardware acceleration for several additional graphics functions, integrates a 135-MHz, 24-bit RAMDAC and programmable clock generator within the accelerator chip, and adds direct hardware support for VESA display power management signalling (DPMS) and the new VESA display data channel (DDC) specification. DDC provides a means for the monitor and graphics card to poll each other for information on resolution and refresh rate support. Full implementation requires a DDC-compliant monitor as well as operating system support, which Microsoft pledges to include in Windows 95.

Installation of the Windows drivers and the STB Vision control panel is accomplished through the use of STB's Windows-based setup program, although the refresh rate-adjustment facilities are DOS programs. (In the next release, these will be integrated into the STB Vision control). You can adjust the refresh rate by selecting a monitor by name from a predefined list or using a standalone utility, but the standalone program, which did not work with the Trio-64-based PowerGraph 64, is much more flexible.

Once installed, the STB Vision utilities provide impressive functionality. Each resolution and color depth is represented by a separate icon within the control panel, but you can also edit these selections in a dialog box you access through the Control Panel. Also, when the Virtual Desktop is enabled, you can switch resolutions on the fly. However, the Virtual Desktop is only currently supported in 8-bit (256) color mode.

The Zoom utility functions within a sizable window to magnify a portion of the screen up to 32 times. There's also the Bird's Eye utility, which lets you move around the screen by clicking on a small iconized representation of the display. The two don't really work together: When Zoom is enabled, clicking on the Bird's Eye window magnifies the image of the icon, not the portion of the screen that you're trying to select. That's because Zoom magnifies what's in the frame buffer.

In spite of the fact that is supports more graphics primitives than the S3 Vision864, including two-point line draws, trapezoid and polygon fills, and hardware clipping, the Trio64 did not improve the PowerGraph 64's performance relative to the older PowerGraph Pro, because the drivers for the PowerGraph 64 haven't yet been optimized to take advantage of the chip's additional functionality. The enhanced drivers, currently in development, should be out by the time you read this.

The two boards achieved nearly identical scores on all our tests, placing firmly in the middle of the range of S3-based boards on all but the 24-bit tests. By pairing its graphics accelerators with fast 45ns DRAM, both PowerGraph boards are able to provide a stable, VESA-compliant display at all resolutions below 1,600-by-1,200. In contrast, many other DRAM-based units fail to maintain the VESA-compliant 75-Hz vertical refresh rate in 24-bit color mode. While STB's entries maintain their refresh rates at 800-by-600 in 24-bit color mode, the DRAM-based boards cannot keep up with VRAM-based products at this color depth.

All in all, the PowerGraph boards combine good performance, interesting and useful features, and low cost to address most users' needs. At its list price of $199, the STB PowerGraph 64 is particularly appealing, and its performance will further improve as drivers that support its enhanced functionality appear in the months to come."
PC Magazine, December 1994