Reasons why the Apple 8.24 GC NUBUS video card is so desirable

[MrFahrenheit]

Having looked over the benchmark data from MacWorld 1993, I’m just left wondering more than anything.

Why do vintage collectors like ourselves want to have the Apple 8.24 GC card in their machine over nearly any other card? Clearly other cards perform better. It was near the bottom of the performance list from the 1993 article.

Is the GC card akin to the Macintosh IIfx? A highly desirable machine “just because”? An LC475 clearly overpowers a IIfx yet sells for 1/5 the price and is less desirable.

What are your reasons for wanting the unicorn GC card? I’m just left sitting here wondering why I should have one or even have one installed in a machine, when there are better options.

I didn’t have any NUBUS equipment at all back when I used vintage Macs in the 90s. I never experienced or read up on them, as they were things I’d never want or need or have money for. So, I’m just trying to experience what I missed out on now.

What are your thoughts?

 

[jeremywork]

I happened across one for not too much before I had my IIfx, so for the last few years it's the only card I've run. I just completed a plethora of IIfx/Nubus video benchmarks in another thread, and while the GC stomps the yard in quite a lot of the tests, it also manages to impact the otherwise unaccelerated draw speed worse than any other (DayStar PowerDemo reveals this point.)

I suspect this is due to one aspect touched on by Guillermo Ortiz in Macintosh Display Card 8•24 CG: The Naked Truth (that such detailed tech docs exist for this card is, in itself, a worthy feature)
(version with images intact begins digital p.78 here: https://vintageapple.org/develop/pdf/develop-03_9007_July_1990.pdf)

Instead of loading all the parameters with every call, GC QuickDraw caches all the data structures it needs, but has to reload the data when changes are detected. Some of the structures cached by GC QuickDraw are color tables, GDevices, GWorlds, PixPats, Fonts, and Width Tables. Changing the pen or modifying the foreground color, for example, invalidates the cached data. To squeeze the maximum out of the 8•24 GC card, it is therefore important to group calls that draw elements with shared characteristics (same color, same pattern, and so forth) instead of constantly changing port parameters between drawing calls.

The two visual tests that fail hardest are color sort and fractal, which give no regard to this principle. In these cases it would save time to turn acceleration off. The effect on the Disk I/O test is more puzzling to me, but I don't know enough to suppose.

The benefits of acceleration on the other hand are greater than most cards, when you consider all the modes combined, and that the card doesn't omit any of them. However, most other cards have a subjectively crisper feel to the Finder UI, especially in late systems like 7.6 or 8.1. To empasize the deficit, the GC is the only card that cannot produce a Jigsaw puzzle that is even remotely smooth in any mode. All the other cards can do it in at least 8-bit color.

The card's memory stats are reported two ways and I haven't confirmed which is more correct. Some sources state the card has 1MB VRAM and 2MB onboard DRAM (GWORLD,) expandable via SIMMs. Guillermo above indicates 2MB onboard VRAM/framebuffer and DRAM via SIMMs only. The 8•24 GC control panel indicates 2048k when no SIMMs are installed and 4096k when my 2x1MB SIMMs are present. So that's something to look into.

Overall though my thoughts about it are as you supposed. It's akin to a IIfx; OEM, chart-topping, remarkably pure in design and execution and as a result expensive and largely unadopted, therefore stunted by obscurity. The fx itself has a memory bus that dramatically outscores the Quadra 950, even overclocked. The IIfx/PDS SCSI Bolt uses the same 53C710 as the Quadra/PDS RAID Warrior and the same devices can score over 9.5MB/s on the IIfx while only hitting 8.5 or 8.0MB/s on Quadra 950 or Quadra 800 platforms. This is all before considering the fx overclocks happily to 50 (or a few more.) I remember a quote from one of the engineers on the IIfx project, when asked by the press about the 'wicked' speed of the system, who lamented his disappointment over not shipping with the (already physically circulating) 68040, and I understand his position now.

As a bonus the CG supports acceleration under System 6, which emphasizes another of the IIfx's tricks.

 

[Phipli]

The big thing for me is that one 8•24 GC can accelerate multiple cheap Vanilla 8•24 or 4•8 cards, meaning you get "free" bonus accelerated cards.

 

[cheesestraws]

Is the GC card akin to the Macintosh IIfx? A highly desirable machine “just because”?

This perhaps is the best way of thinking about it: it was the flagship of a generation of cards, but was swiftly superseded by faster things. But because it was once top of the range, it retains that cachet,

 

[IIfx]

It pairs with the IIfx, so it just picks up the aura of the system it was meant for.
I’d like to have one for the sake of completeness, but the Radius/Apple 24 bit card I have is working well.

 

[Crutch]

Was the 8•24 GC actually “meant for” the IIfx in particular? (I know lowendmac says this, but that doesn’t mean it’s true.) I had one in my IIci (which came out 6 months before the IIfx), I’m pretty sure circa 1990. It was just a NuBus card that ran in all the NuBus Macs, right?

 

[beachycove]

It does not require a IIfx, no.

I think much of the association with the IIfx is that the 24GC so nicely complements the co-processors/ controllers unique to that machine, in the 24GC’s having not only a Quickdraw processor but an actual operating system that boots up, running the Nubus card. A IIfx with a 24GC is thus a complete package and something of a multiprocessing wonder, of that era of course. Rather like the 840av/660av models later on, this approach was obviously meant to bypass some of the limitations of the Mac OS, as well as to engineer an overall more responsive machine. Nevertheless, said limitations notwithstanding, the fact that the IIfx can do this in System 6 is a added bonus, since System 6 is so fast already on any 68030, never mind the hyperactive one found in the IIfx.

I had a IIfx complete with a 24GC card for a few years and it was satisfyingly nimble, but eventually I sold it on to another 68kmla-er as the machine was too big for my setup, and so very, very loud. The latter was for me the real problem, as I can’t abide noisy computers, and it did not get much use.

 

[jasa1063]

I just acquired one. The reason I wanted one is that I remember reading about it years ago I was always fascinated by the fact it had an onboard Am29000 RISC CPU. It was like so many other things with Macs at the time, it was way out of my price range costing $2000 in 1990 . Now all these years later I was able to get one for under $100. I have it in one of my IIci computers maxed out with 128MB of memory, ROM-Inator II and Daystar PowerCache 50MHz accelerator and BlueSCSI. I am still looking for a compatible memory upgrade for it.

 

[Iesca]

I have a 4•8 that came with my Mac II and which I've upgraded to a 8•24, but it would be nice to have an 8•24 GC to pair with it for that added graphics acceleration. Seems like it would essentially be like adding an extra 'GPU' of sorts.

 

[jeremywork]

This is in the ReadMe for Macintosh Drag and Drop v1.1:


This is probably the source of visual artifacts from 7.1.1 (P) forward. Any use trying to strip it from later versions?

 

[olePigeon]

@jeremywork Very interesting find. I'm going to have to break out my card and give it another go next week. Make sure I don't have Drag & Drop installed.

Their solution is to remove the 8•24 GC Control Panel; but don't you need the Control Panel for acceleration?

 

[jeremywork]

Their solution is to remove the 8•24 GC Control Panel; but don't you need the Control Panel for acceleration?

Yep, same solution was offered when the user accidentally bought a Quadra.

Your engine will stop making that terrible noise if you ride your bicycle instead...

 

[IanBetteridge]

Was the 8•24 GC actually “meant for” the IIfx in particular? (I know lowendmac says this, but that doesn’t mean it’s true.) I had one in my IIci (which came out 6 months before the IIfx), I’m pretty sure circa 1990. It was just a NuBus card that ran in all the NuBus Macs, right?

Hello! First time poster, I happened on this when I was trying to find an image of the launch t-shirt for the IIfx… anyway, I was working at Apple UK in IS&T when the IIfx was launched, and the 8 24 GC was launched at the same time in 1990. They were seen as a pair for someone who wanted the most powerful Mac possible. So yes, you could of course use it with other Nubus Macs - but they were launched together. I think A/UX 2.0 was announced at the same time, and a lot of the internal chatter was that the combination of the three was really the future of the Mac.