Michael Roeder reports: I bought my Macintosh Centris 610 way back in 1993. It’s been a reliable and fun replacement for my Mac Plus. Because I have some way cool computers at work, I haven’t had the need to buy a new Mac of my own.
The performance of my SuperMac Video Spigot was a little poky, however. Also, the Centris comes with a 20 MHz 68LC040, which means it doesn’t have the Floating Point Unit (FPU). Thus certain cool software, such as Macromedia’s Extreme 3D, won’t work. I tried a shareware FPU emulator, but it didn’t work with all software, and when it did work it was slow.
Replacing the CPU with a full 68040 was one option. Apple’s Developer Notes state that the only difference between the Centris 610 and the Quadra 610 is the clock speed; both have the FPU support code in ROM. (In fact, some Quadra 610s came with 68LC040.) A 68040 would cost $200.
Sonnet offers two products for the Centris 610, a Quad Doubler with 68LC040 for $200 and one with 68040 for $300. I decided to buy the accelerated 68040 with FPU.
The Sonnet Quad Doubler is a circuit board about 2″ wide by 4″ long. One half has a zillion pins on the bottom to match the pins on the bottom of a 68040. The other half has a 68040 with a gnarly heat sink on top. There is additional circuitry to make the 68040 run at twice the clock speed of the Centris or Quadra it’s plugged into. (There are two different models. The BST-40F, for the Centris 610 only, costs $300; the BST-50FA, for the Quadra 610, costs $400. Sonnet says that the BST-40F will not work reliably in a Quadra 610.)
Installation is pretty simple. The instructions that come with the Quad Doubler are clear and well illustrated. You open the case and remove the original CPU. The kit comes with a little tool you use to gently pry up the CPU. Then you plug the Quad Doubler into the CPU socket. If you have a NuBus card plugged into your Centris, you have to first remove it to expose the CPU – but surprisingly enough, there is room for it to go back, even with the big heat sink on the Quad Doubler. Put the case back on, plug everything back in, and you’re in business.
There is no software to install. Just as the instructions promised, my Centris booted right up without any problems. I wanted to see how fast this new 40 MHz CPU really ran, so I tried some performance tests I had made with Macromedia Director. I didn’t expect to see an actual doubling of performance – after all, the rest of my computer was still running at the same clock speed as before. But I was pleasantly surprised to see that animations were running about 56% faster than before, enough to boost performance from somewhat canine to snappy. And with the full 68040, those apps that needed the FPU now run without a hitch. (If you have a software FPU emulator, you should disable it before you install the Quad Doubler.)
An added benefit is that my Video Spigot now performs that much better, too. At 20 MHz, it had always created strange diagonal flashing artifacts in video it was capturing, and video was jerky. But with Quad Doubler the video quality is up to acceptable levels. (You won’t be able to capture full-speed 640 x 480 video, but the video you do capture will look better than before.)
I have no data about Sonnet’s technical support because I never needed to call them: the Quad Doubler simply works.
The Sonnet Quad Doubler does not provide the performance boost of a Power PC upgrade – but neither does it cost that much. For $300, it’s probably the best performance upgrade you can buy for your Centris. (The Quad Doubler for the Quadra costs $400. Its relative increase in performance over the stock Quadra 610 may not be as impressive, but it would probably still be worthwhile.)
*The Video Spigot NuBus card is about three inches too long to fit in the Centris/Quadra 610. You can make room, however. You have to cut out the shelf that holds the hard drive and rig new brackets so it’s lower and further forward. It’s a scary proposition, but if you have basic carpentry skills, it should work fine.
Michael Roeder is a Software Quality Assurance Engineer at Macromedia. In his spare time he is an elf who plays hockey, rides a motorcycle, and watches Babylon 5.
Keywords: #sonnetquaddoubler #quaddoubler