Ultra-Fast SCSI You Can Use

Most Ultra2 cards lack connectors for typical external desktop devices. Adaptec's new card changes all that.

Jon L. Jacobi, special to PC World

I'll admit it: I'm a total speed freak when it comes to computing. I'm always looking for ways to squeeze a little more performance out of my system. But speed isn't just about processors: Increasingly, the hard drive is the major performance bottleneck on today's PCs. In my experience, a really fast Ultra2 SCSI hard drive--matched up with SCSI CD-ROM and CD-R drives--can make the difference between a reasonably quick system and one that will knock your socks off. The only problem with putting together this kind of setup is that most external SCSI desktop peripherals need a 50-pin adapter. Until recently, all the Ultra2 cards on the market have come with 68-pin external connectors.

Adaptec Puts It on the Desktop

Adaptec, the leading provider of SCSI adapters, has leaped into the breach by providing an Ultra2 SCSI adapter designed for the average desktop PC.

To quench your thirst for better drive performance--and allow you to hook up to typical desktop external devices--Adaptec developed its new 2930U2 Ultra2 LVD PCI adapter. Marketed as a lower-cost alternative to the company's $399 2940U2W, the 2930U2 sports a list price of $315. I searched the Web for the lowest prices on both controllers and found each commonly available for around $250 on average; but the price on the new 2930U2 should drop even further as it becomes more common. Aside from popular external desktop SCSI devices, such as removable cartridge drives and SCSI scanners, it also handles the new Ultra2 Low Voltage Differential drives. Despite the current parity in street price, many users will prefer the 2930U2's convenience. It has a high-density (SCSI-2) 50-pin external connector, which is the format used by most desktop peripherals. All the other Ultra2 or Ultra Wide controllers I'm aware of still have 68-pin connectors only.

Ultra2 LVD SCSI has two advantages over other technologies. The most impressive is its 80-megabytes-per-second maximum burst transfer rate. That's double Ultra Wide SCSI's 40MB per second, and more than double EIDE UDMA's 33MBps rates. But performance isn't the whole story: Ultra2 LVD SCSI's maximum cable length of almost 30 feet dwarfs EIDE's 18 inches and more than triples non-LVD SCSI's 9 feet.

The 2930U2 also has two internal connectors, a 50-pin and a single 68-pin Ultra2 LVD, which brings us to the Ultra2's only disadvantage: You can attach Wide, Ultra Wide, or Ultra2 drives on the LVD cable, but your Ultra2 drives will be limited to 40MBps rather than 80MBps. A good rule of thumb is not to mix Ultra2 and slower devices on the same cable. Users with legacy wide drives should opt for the 2940U2W, which has an additional internal 68-pin connector for use with the slower drives.

Scorching Performance

To get an idea of the 2930U2's performance with non-Ultra2 SCSI devices, I attached a variety of drives including a Toshiba XM-6201TA 32X CD-ROM, Plextor's PlexWriter 8/20 8X CD Writer, and an IBM DORS-32160 2.1GB Ultra SCSI drive. I even checked Ultra Wide performance with a Plextor UltraPlex Wide 40X CD-ROM drive running alone off the 68-pin Ultra2 channel. Our test system used a Pentium MMX-200 system with 32MB of SDRAM. Performance was excellent, on a par with other Ultra and Ultra Wide controllers I've tested.

But Ultra2 LVD is about speed, so I also tested the 2930U2 with a 10,000 rpm, 18.2GB Ultra2 LVD Seagate Cheetah drive--the fastest drive on the market, bar none. The results were impressive. Not only did my informal benchmarks show it to be the fastest controller/drive combo I've tested to date, but Windows seemed to jump into overdrive. Applications popped onto the screen as if shot from a cannon, and task switching was much faster.

To gauge how much of this performance could be attributed to the speedy Cheetah drive, I used the 2930U2's BIOS to limit the maximum transfer rate to 40MBps (Ultra Wide). I noticed no speed loss at all. Adaptec says that this is normal performance when only one drive is hooked up, but the 80MBps burst transfer rate means there's considerably less degradation in performance when multiple devices are attached and in use. At the very least, Ultra2 means you're compatible with the next generation of drives, and have a lot more cable length to play with.

So if you're starting to get annoyed with your system performance, think twice about buying a faster processor. You might get more bang for your buck by adding a 2930U2 controller and a speedy Ultra2 drive.