DFI 486/33. (computer) (Evaluation)
by Denny Atkin

When I first powered up the DFI 486/ 33 with local bus video, my thoughts immediately turned to a line from a classic song by the Who: "I don't wanna cause no fuss, but can I buy your magic bus?"

The DFI 486/33 is one of the first relatively low-cost PC clones to feature local bus video. The computer's Super VGA graphics subsystem is directly addressed by the 486DX microprocessor, which gives you graphics performance three times faster than that of typical 16-bit Super VGA cards. Display data doesn't have to pass through the slow 16-bit ISA bus slots found on traditional PCs, but it can instead be sent directly to the chip set 32 bits at a time, at a speed much higher than the 8 MHz of the typical PC expansion bus.

Local' bus is the second big innovation to hit PC video within the last year or so; the first was the Windows accelerator card. Windows accelerators may actually give you more speed than a local bus VGA setup--but only while you're running Windows. These cards have custom processors designed specifically for speeding up Windows and a .few other applications, such as AutoCAD. But if you're not running Windows, your graphics performance with one of these cards will normally be no better than with a vanilla VGA card. Local bus, on the other hand, speeds up all screen operations. If you don't live in Windows and want top performance for DOS-based graphics applications or game software, local bus is the way to go.

One important concern with local bus video is that it doesn't use ISA expansion slots. Early local bus implementations used custom, nonstandard slots or put the video circuitry on the computer's motherboard. In mid June, however, the VESA committee defined a standard for future local bus implementations.

DFI's local bus implementation predates the VESA standard. It's a unique hybrid of the custom slot and motherboard setups. Both the 486DX processor and the video setup are on a custom card with two connectors. One connector plugs into an ISA AT slot, while the other plugs into a custom slot that's in-line with the AT slot. The processor and its support circuitry are on the custom card, but the system's main memory and cache RAM are on the processorless motherboard, which DFI calls a station board. Putting the processor on a card makes processor upgrades literally a snap. The station board can hold up to 48MB of RAM, and an additional 16MB can be added using a 32-bit memory card.

The system I tested was configured with a 486DX running at 33 MHz (386DX and 486SX configurations are also available), 4MB of memory, 256K of processor cache memory, a crystalclear 1024 x 768 noninterlaced Super VGA monitor, a 200MB Maxtor IDE hard drive, and 3 1/2-inch and 5 1/4-inch floppy drives. The station board has eight expansion slots, six of which are available. One slot is occupied by the processor/video card, while another holds a DFI All-in-One expansion card, which includes floppy and IDE hard drive controllers, two serial ports, a parallel printer port, and a game port. Ribbon cables extend from this board to the COM2 and game port connectors, which block an adjoining slot. If you need to fill all six open slots in the computer, you'll have to sacrifice the use of these two ports.

The system case is fairly plain, but not bad-looking. Reset, Turbo, and Power buttons adorn the left front. These buttons are flush with the front of the unit and must be pressed in fairly far; it's unlikely you'll accidentally reset or turn off the machine. With both floppies installed, there's still a spare 5 1/4-inch drive bay, suitable for a tape backup or CD-ROM drive. three-button serial mouse is Microsoft and Mouse Systems compatible, and it has a quality feel. The only really weak link in the system is the keyboard. DFI uses a Key Tronic enhanced AT keyboard, but it must be Key Tronic's bottom-of-the-line model. The keyboard is very light, and the keys feel very mushy. I'll admit, however, it's one of the quietest keyboards I've ever used, and I did eventually adjust to the keys' lack of positive feedback.

Of course, if you're purchasing a 486, performance is probably a big concern. With its speedy processor, 256K of ultrafast cache RAM, and local bus video system, I never spent any time waiting for the computer. Word processor macros that take five or six seconds to execute on the 386SX/16 I normally use were practically instant on the DFI. Windows screen updates were incredibly quick; even running in 256-color 800 x 600 mode, Word for Windows scrolled through documents with no stuttering at all. Graphics-intensive games such as Aces of the Pacific run silky smooth. The Tseng ET4000-based graphics subsystem includes 1MB of RAM and supports resolutions up to 1024 x 768 in 256 colors.

The system's documentation is great from a hardware-configuration standpoint, but it never pretends to be a tutorial on how to use the machine. You'll have no trouble setting up the system or adding peripherals to it, but if you're new to MS-DOS computing, plan on buying a good PC tutorial book with the system.

The DFI 486/33 is a real gem. Although the configuration/tested retails for $2,495, DFI says the actual street price is likely to be 2530 percent lower than that. Of course, after using a system with performance like this, I'm hooked. To paraphrase the Who, "I don't care how much I pay, l wanna drive my [local] bus with you everyday."