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. | Road Apple: Mac IIsi
The great compromise was taking a good hardware design and running it at 20 MHz despite the fact that each and every component was capable of running at 25 MHz. (Apple didn't want to cut into sales of the IIci.) Like the SE/30, the IIsi has a 68030 processor direct slot (PDS). Unlike the SE/30, it runs at 20 MHz, twice the speed of a NuBus slot and 25% faster than the one on the 16 MHz SE/30. Unlike the SE/30, it is possible to put a NuBus adapter in this slot. Like the IIci, it used the first bank of RAM for video. Unlike the IIci, the first bank of RAM was 1 MB soldered to the motherboard. This allowed Apple to cut costs by installing only one bank of SIMM sockets. It also limited expansion to 65 MB -- pretty good, even by today's standards. The IIsi was a very competent computer with few compromises. If it had used VRAM like the LC, it would have been a bit faster. If it had run at 25 MHz, that would have been nice. (BTW, the IIsi is frequently chipped to 25-28 MHz, providing the true capability of this design.) With a 68040 accelerator in the PDS, the IIsi holds its own against a Quadra. However, the IIsi power supply, perfectly adequate for normal use, may be inadequate if you install a different hard drive, a video card, or a PDS card (such as an accelerator). The NuBus slot in the IIsi is rated at just 13.3W, less than many high resolution or 24-bit cards require. The PDS is rated at just 7W. The normal hard drive draws 6W; if you replace it with a higher-draw drive, power to the NuBus slot or PDS is reduced accordingly. Not a bad little computer at all, just one compromised to
avoid stealing IIci sales. Details
For more information on the IIsi, click here.
| . |  System Profiles  Mac Resources
| . |
It's
debatable whether this is really a Road Apple. The IIsi was
a bit of an odd duck. On the one hand, it was the only Mac
II to ship without a NuBus slot. On the other hand, it could
be seen as a monitor-less SE/30.