Peering inside the aluminum ball: Woodcrest, Conroe, and the “pro” Macs

Saying farewell to the G5

With some knowledge about Intel's CPU lineup and an understanding of how Apple has positioned its pro desktop line for the past three years, it's time to make some predictions about what we might see when Steve Jobs lifts the curtain on the G5's successor machines when the time comes in August.

Lately, the biggest debate has been over the choice of CPU. Early on, most bets were on Conroe. It has almost everything Apple would want in a desktop CPU: it's fast, has a low TDP compared to the G5, it has 4MB of L2 cache. The Bad Axe 975 motherboard even supports Firewire 400. However... it doesn't do multiprocessor.

The question then follows: in the age of dual-core CPUs, does a multi-CPU box still make sense? Apple thinks so—look at the Quad G5. Two CPUs, four cores. That's a lot of horsepower for applications such as HD video editing, compositing, rendering, animation, audio editing, and other processor-intensive tasks.

Apple is prone to sudden and unexpected changes of course, but I don't expect one to happen here. Apple will keep a "God Box" at the top of its Pro Mac lineup, and I'm all but certain that it will be another Quad: a four-core, dual-chip machine. In order for that to happen, that means Woodcrest at the top of the line. That's right, the next desktop Mac you buy may have a Xeon inside; if it has two of them, it won't cost much more than the current Quad G5.

Why Woodcrest?

The prime candidate for the high-end Pro Mac workstation would be the Xeon 5160. It's clocked at 3.0GHz (enabling Steve Jobs to finally reach the magic 3.0GHz number—albeit two years late and on an entirely different architecture) and has a 1333MHz FSB. It's also pricey: US$851 in quantities of 1,000. Now that Intel has a one-price-for-everybody model, Apple shouldn't count on any deep discounts. So we're looking at US$1,700 for the processors alone. Add in another US$400 or so for a high-end video card, another US$400-500 for the motherboard, and the price rapidly escalates—perhaps beyond the US$3,299 of the current Quad G5. That could mean Xeon 5150. That's still a respectable 2.66GHz and is US$161 cheaper than the 5160.

The other option for the high-end machine is the Conroe XE, or the Core 2 Extreme. That would fit the bill with the cache and clockspeed (up to 3.33GHz in 2007), and its TDP of 75-80 watts would feel a bit more familiar to those upgrading from liquid-cooled G5s. Again, you run into the same limitation: only one Core 2 Duo/Extreme per machine.

Aside from the ability to use two or more processors, Woodcrest has two more advantages over the Core 2 Duo: memory and bus speed. As mentioned before, the chipset that Intel has announced for the Xeon 5100 series uses FB-DIMMs. I gave you the sort-of-long story before, and I'll summarize the short version here: you can use massive amounts of lower density RAM with an FB-DIMM. So memory speed is another advantage for Woodcrest.

Currently, Conroe is limited to a 1066MHz FSB. While impressive—especially if you're upgrading from a G4 tower—it lags significantly behind Woodcrest's upper limit (on the Xeon 5130 through 5160) of 1333MHz. Note that this very high FSB speed is essentialy for getting the most out of the FB-DIMMs—the extra chipset-to-memory bandwidth would be a waste if there weren't also a higher bandwidth pipe between the chipset and the CPU.

So currently, Intel's Xeon and Core 2 platforms are stratified primarily along memory and frontside bus bandwidth lines, and secondarily along the lines of clockspeed and cache. This distinction is going to be important when thinking about how Apple will stratify their offerings. Gone are the days when Apple can demarcate the different levels of their lineup along the lines of clockspeed and cache. We're now entering an era where system bandwidth and architecture will mark the difference between products. More on this later, though.

The cost of a Xeon quad

Woodcrest could get expensive, that's for sure. It's difficult to say how much it would cost Apple to put a system together, but what we can do is spec out what might be a system similar to what Apple would offer. We found all of our prices via the Ars Technica Dealtime Shopping Engine.

First, we need a processor. We can get two Xeon 5150s for US$760.99—almost US$70 more than Intel's list price. Those CPUs need a motherboard, so lets grab a SuperMicro X7DAE 5000x-based motherboard. It's loaded: 8 FB-DIMM slots for up to 32GB of RAM, a dual-port gigabit Ethernet controller, 6 SATA-II ports, 2 PCIe slots (1 x16 and 1 x4 in x16), 3 PCI-X slots, and a single 32-bit PCI slot. We found one for US$475. We also need some heat sinks for those bad boys; let's plan on US$100 for them.

Now we need some RAM for this beast. We can grab some RAM from Crucial—say 2 512MB FB-DIMMs—for US$202.99, which will replicate the 1GB of RAM offered on Apple's high-end MacBook Pro while leaving six slots open. For video, let's go with the Radeon X1900 XT, which is another US$389.99. A nice 650 watt power supply costs US$150 and the Cooler Master Stacker 830 case foes for US$239.99. We can drop in a 250GB Hitachi Deskstar T7K250 SATA hard drive for US$80 and we need a DVD burner, so lets grab the BenQ DW1650 for US$39.49. Add an Apple Keboard and Mighty Mouse for US$70 and our machine is good to go.

The retail price for what would be a very high-performance workstation (sans OS)? US$3,269.44.

Ouch.

Apple won't pay anything near that, primarily because manufacturers don't play retail for parts. On some commodity items like the keyboard, mouse, and power supplies, the markdown will be substantial; on other items that require heavy engineering and development costs (such as the motherboard), it will be much less. For the sake of argument, we'll assume Apple pays 12.5 percent below the best prices we could find for each component, with the sole exception of the CPUs—Intel makes its prices for OEMs like Dell, HP, and Apple public.

According to Intel's price list, the Xeon 5150 is available to manufacturers for US$691 each. Intel has apparently decided on a one-price-for-everybody model these days, so we'll assume that's what Apple pays for the Xeon 5150. That means a cool US$1,382 for Van Halen's favorite CPUs.

With our 12.5 percent discount, Apple would pay US$2,911.03 for the Quad's parts. Add in a respectable 20 percent margin to keep AAPL shareholders happy, and we end up with a Quad Xeon Mac for US$3,493.23 and offer users the ability to customize it with dual Xeon 5160s for a few hundred more. Given that Apple has historically had margins upwards of 25 percent for its computer hardware, the 12.5 percent discount is a conservative one.

Keep in mind that these prices don't include assembly, but that is a relatively minute part of the total (for example, research firm iSuppli estimated that the G4 Mac mini cost US$274.69 in components and less than US$9.00 to manufacture).