The LC 580 (a.k.a. Performa 580 and 588) is essentially an LC 575 with a new logic board that supports an IDE hard drive (instead of the more expensive SCSI hard drive used in earlier 500 series Macs) and uses a less expensive monitor.
This was the last Mac designed around the 68040 processor. The Quadra 630 was designed to replace the Quadra 610.
he LC 575 (a.k.a. Performa 575, 577, and 578) is essentially a Quadra 605 motherboard in an LC 520/550 case.
First available in Canada (1993), and then Asia and Europe (and never sold in the home US market), the Colour Classic II (also known as the Performa 275) shares the motherboard design of the LC III. Running at a relatively fast 33 MHz, memory can be expanded as far as 36 MB.
At 33 MHz, the LC III+ (also known as the Performa 460) was the fastest 68030-based computer in the LC series.
The LC 550 replaced the LC 520, increasing CPU speed from 25 MHz to 33 MHz. It was released at the same time as the 68LC040-based LC 575.
What was the smallest desktop Mac prior to the Mac mini? Apple’s LC series, which measured just under 3″ tall, although it had as big a footprint as four Minis. And the Quadra 605 (also known as the LC 475 and Performa 475 or 476) was the most powerful model in this diminutive line.
Take an LC III and graft on a 14″ Trinitron monitor along with stereo speakers. That’s what Apple did to create the 520.
This relatively rare variant of the LC 630 includes a DOS card with an Intel 486DX2/66 CPU, although some shipped with a Cyrix 486/70. The DOS Compatibility card can share Mac motherboard memory or use its own dedicated RAM.
“With double its predecessor’s speed and more than triple the RAM capacity, the LC III is a significant entry into the low end of Apple’s line.” MacUser, April 1993