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Apple’s 16-bit Solution

I was saddened to read of the Quadra 700’s demise. Once again, Apple has cancelled a model which, despite clear advantages, doesn’t fit into their price and product line structure. In the process, Apple complicated the issue of cheaply achieving 24-bit color.

When Apple introduced the Quadra 700 and 900 as the first 68040-based Macintoshes, there was much consternation about price, features, upgrades, and compatibility. The 700 and 900 feature much the same technology, with Ethernet, room for 2 MB of video RAM (VRAM), a 25 MHz 68040 with built-in math coprocessor, and improved access to internal components. Apple quickly replaced the 900 with the 950 (a 33 MHz 68040), making the distinction between models more apparent. With some price cuts and the passage of time, most pricing and compatibility issues disappeared.

Apple’s introduction of the IIvx last fall, followed recently by the Centris 610 and 650 (16 MHz and 25 MHz 68040-based machines) tarnished the Quadra 700’s sheen. The new Quadra 800, which has a similar price and footprint to the 700, but at 950 speeds, also deadened the impact of cutting the 700.

However, everyone has ignored the fact that the Quadra 700 has a feature not shared by the Quadra 800 or the two Centris models: room for 2 MB of VRAM. Although this seems minor, I believe it to be a crucial underestimation by Apple of the necessity for 24-bit color in the near future. This is primarily true for users of Kodak’s Photo CD and color flatbed and film scanners, with lesser importance for users of multimedia and CD-ROM-based video. The Quadra 800 and Centris models, as well as the IIvx, LC, LC II, LC III, and Duo Dock for the PowerBook Duos all max out at only 1 MB of internal VRAM. This amount of VRAM provides 32,768 colors, or 16-bit video. Only the Quadra 950 can still do 24-bit video without an additional video card.

Apple’s rationale is two-fold. First, 16-bit video is more than adequate for video replay and most multimedia. Although full-screen, full-motion, 24-bit-per-pixel video capture is possible with such devices as SuperMac’s Digital Film board, for the sake of compression and sanity, most video is sampled down to 16 bits, or initially digitized at that bit depth. No more than 16 bits is necessary for representing the dynamic range (or numbers of discrete colors) that occur in a standard video signal. Therefore, you achieve a great savings in storage and an increase in digitizing and playback speed.

Second, Apple believes that few non-experts can distinguish between 16- and 24-bit video (see May-93 MacUser article on large monitors for a taste test they performed). Kodak Photo CD actually uses a 16-bit colorspace (the PhotoYCC colorspace), which is compressed from and decompressed into the conventional 24-bit RGB colorspace.

I maintain that Apple’s rationale, although valid in general today, is not a significant enough reason to limit users to 1 MB VRAM, and may change in the near future.

On the first point, although today’s standard is NTSC in the U.S. and PAL and SECAM abroad, none of which allow for terrific dynamic range, future standards will allow for substantially crisper displays and broader ranges and distinctions of color. Coupled with this is the rapidly decreasing cost of storage and rapidly increasing speed of retrieval, currently major limitations in video storage.

On the second point, I feel that you don’t have to be an expert to appreciate 24-bit video. I have spent the last 20 months working mostly on systems with 24-bit video, and the distinction that I see between those systems and others running 16-bit video is substantial enough for anyone making a cursory comparison to notice. People doing serious illustration using either a PostScript language drawing program like Adobe Illustrator or a bitmap-oriented program like Fractal Design Painter, or doing any sort of photographic manipulation, correction, or compositing in Adobe Photoshop, must have 24-bit video. Although you may see smooth blends and crisp results on screen in 16-bit color, you will have no guarantee of the actual output colors or blends. The new calibration products for the truly serious that are about to come on the market (Kodak’s ColorSense system, and products by Agfa, EFI, and others) essentially require 24-bit color.

Apple ostensibly is increasing the market potential of their products by eliminating some circuitry and a few SIMM mounts. I can’t imagine this saves more than $15 per machine – probably less since the parts exist in other Macs. Engineering costs are negligible because Apple already designed the Quadra 700, 900, and 950. By the time you go through mark-ups, these missing SIMM mounts and circuitry might translate to no more than $50 on the price sticker.

For the user, however, 24-bit color is more expensive. The internal circuitry in the Quadra 700, 900, and 950 is estimated at approximately 75 percent of the speed of the Apple 8*24GC video display & QuickDraw accelerator card (which displays 24-bit color only on 13" monitors; it drops to 16-bit color on 16" monitors). On the other hand, using onboard video equipped with enough VRAM slots, with the addition of six 256K VRAM SIMMs at a street price of $150 total, the user gains 24-bit on a 13" or 16" monitor (including the capability to use third party monitors), avoids using a NuBus slot, and achieves speeds comparable to a $450 to $600 video card from SuperMac, Radius, or RasterOps. (The Quadra 900 and 950 require only an additional four SIMMs or $100, as they comes with 1 MB of VRAM installed.)

Although video cards from third parties often include extra features like automatic dimming, multiple video modes or pixel pitches, and, with the E-Machines 16" video card, even a 10BASE-T Ethernet port, many sophisticated users never use these features (humbly, I include myself in that group).

To give you the same capacity as a Quadra 700 (two slots and 24-bit video on a 16" video), the Quadra 800 would cost an additional $450 to $600 and would lose a slot. The net difference after subtracting the VRAM cost is $300 to $450 (or 10+% of the cost of the machine extra) for what might have added $50 to the machine’s cost.

In an effort to reduce cost, I believe Apple made it harder for many individuals to achieve 24-bit-hood. With the increasingly lower cost of the entire Apple product line in conjunction with lower prices for scanners and the advantages of Photo CD, it becomes harder for users to achieve 24-bit color without exceeding their budgets. The elimination of the Quadra 700 provides an easy way for Apple to slip the Centris computers in the middle of the product line since the Centris 650 and the Quadra 700 are virtually identical in performance. Ultimately, users suffer by their lack of inexpensive expansion. The beauty of Apple’s newer machines, such as the PowerBook Duo and Duo Dock combination, is that you can have expandability without paying for it until you need it. Now you’ll have to pay more.

The good news is that Apple is clearing out Quadra 700s at prices 50 percent or more below what they were six months ago. The Quadra 700 in the 4/0 configuration is available for $2,000 street price versus $3,800 on 01-Sep-92. A Quadra 700 in the 4/200 configuration is $2,600 street price versus the Centris 650 8/230 for $3,100. Remember the above calculations show that if you need 24-bit video, the 700 4/200 would be $2,750 versus at least $3,550 for the equivalent Centris 650 with a 24-bit video card.

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