Mike Ford posted the following to Vintage Macs, our group for users of pre-PowerPC Macs.
Well, people asked, and people sent me info, and I got curious and went hunting myself. This is a brief collection of what I have found, and what I believe to be accurate, YMMV, corrections and additions welcome.
The 8•24GC was Apple’s response to the third party high end prepress raster image processing cards (RIP) that were selling for thousands of dollars. It uses the same AMD 29000 RISC processor, and it is FAST.
How Fast Is It?
That depends, some things that don’t use the functions it has accelerated will have no gains, but Apple did integrate the card with existing QuickDraw functions via the 8•24GC control panel. Estimates I have seen rate the speed up as 5 to 30 times faster than built-in video, and rank it as about the speed of the internal video on the 8100 PPC. It is fast.
Will it run on a Quadra?
Yes, but not with acceleration. It is designed for a 68030 machine, I suspect the IIfx primarily, but it will accelerate any 68030 with a full length NuBus slot. I am not sure about the Mac II with a 68020, but suspect it to work.
Which OS will it run under?
Apple says system 6 and 7.0, but there are two issues with that. First Apple is being conservative and like usual unwilling to support an old part if it can wiggle out of it. The second is that the 8•24GC had a rev A, B, and C, with ROM versions divided into 1.0 and later. What I have read is that the early ROMs, the 1.0, had some conflicts beyond system 7.1, but that later ROMs worked pretty well up to 7.6.1 with only cosmetic problems (menu display looks garbled sometimes, but still works). The 8•24GC control panel I suspect is the key, and it is part of the 7.0 release, and still “works” in 7.6.1. I am going to play with some OSes on my IIfx and see what I find out. For the moment I have just tried 7.1 and with that it is great.
Golly, How Can I Find Out More?
The usual, DejaNews, Apple tech support, etc., 8•24GC may have trouble with the “•”, but 24GC works OK in a keyword search. Below is a good link to start with, and an excerpt from it.
APPLE 8•24GC ACCELERATED GRAPHICS DISPLAY. This can be used in any NuBus Macintosh that supports full-sized NuBus cards (including NuBus Power Macs). It will provide 24-bit color on any such Mac, and will work in accelerated mode on any 68030 Macintosh. It supports 1152 x 870 Color displays in 256 colors and has 2 MB of DRAM (expandable to 10 MB). This card is not compatible with Virtual Memory or RAM Doubler in accelerated mode, but it will work fine with them in unaccelerated mode. <article goes on in detail>
How Do I Fill Up Those Two SIMM Slots?
Apple is the suggested source, but NOBODY I talked to anyplace has ever seen or heard of these SIMMs in actual practice.
Where can I find one of these most wonderful cards?
Funny you should ask, but I have a ROM 1.1 in my IIfx. I am going to play with it for a week or so, then the IIfx most likely turns into a server for my LAN, and the card can go to whoever wants it the most. At least one other member of the list has one (no idea if it is for sale), and at Macs4sale they have some for $45 plus shipping, handling, packing, etc.
Please don’t take this as bad mouthing the competition, but I have two problems with Macs4sale: they wouldn’t tell me what the shipping and handling charges were, and they don’t know the ROM version of the cards they have. I did squeeze out of them that they have rev A, B, and C cards, and I am willing to bet that those that don’t specify will get older cards. The only way I know of to find the ROM rev level is to put the card in a Mac and use a program that reads the data off the ROM (I used TattleTech). I have no idea how the board rev level might relate to the ROM version either.
If you are interested in my rev 1.1 ROM 8•24GC card email me directly. If I was still working directly on my Mac II series machines you couldn’t pry this card away with a crowbar, which might explain only two being offered for sale in all of the DejaNews archives.