jesteraver said:
One thing would be nice to see a 4 x Intel Quadcore PowerMac, I for sure would have no use for it, but I have a feeling many people would need something that powerful. Would be interesting too see the amount of memory that would go with that sucker.
Speaking as someone who for a living helps determine the design for systems that use two or more processors inside them I'd like to comment on this from that perspective.
This is a botique system, beyond apple, beyond IBM, beyond HP, Beyond Dell.
The reason I say that is that once you cross from a two socket to a for socket system certain assumptions are made in the base chipsets.
First, there is one of them for Intel processors that is generally available. That is Intel's 'Caneland' Platform, or also known as Twincastle.
The first and primary challenge for that chipset is that it was not designed to do a 16x slot out of the chute. THis doesn't mean you couldn't do it, but if you check out Dell or HP's website and look at the 6850/DL580 G4 you'll notice the PCI-E slot layout should be identical. Several 8x's I believe it is.
IBM Makes a Xeon 7000 class chipset called EXA or Enterprise X-Architecture. It currently is PCI-X 2.0 only, with PCI-E on the horizion but 8x maximum per slot, and video is not supported.
So someone would need to get Intel's permission, and the chipset would have to be able to support 16x slots. I've not seen the low level details of twincastle in a while, but I don't believe it can even do this without a new I/O southbridge, or if the northbridge has enough bandwidth to do it.
The second problem is power consumption. Intel's new 7100 processor at the top two speeds consumes 150W of power maximum per socket, the two slower ones are 95W maximum. But just think, your average system would need about 1200W power supply, or twin 600W. If you're in the US that's reaching the very edge of what 110V can drive and maintain UL listing.
Then there's the cost. I believe the average list price for the 3.3GHz/2M/16MB L3 chip is $4899. Don't let the websites fool you when the announces and they say the price is $1850. That's the price to someone who buys 1000 at a time. Then you also have to factor in the heatsink, and the VRM. Those are not inexpensive to make (well that is, you could probably slap something together and have it fail a lot)
The final problem, and the most damning in my opinon, is the architecture itself.
The FSB for memory on the Mac Pro today and the Core Solo chips is 25% faster. Shortly, it will be 40% faster. Xeon 7100 has a 667MHz FSB and a 800MHz FSB. Woodcrest has a 1066MHz and clovertown should have 1333MHz. To put one of my favorite engineering comments I've heard at a conference when this was asked 'why' the answer was: Physics is a Bitch!
The more processors you have, the more wires you have, the harder it is to get it up in clock speed. Historically the quad processor socket systems have always been behind. When Two socket was 800MHz, Four socket was 400Mhz, when Four socket was 667MHz, Two socket was 1066MHz, when two socket was 400Mhz, Four socket was 133MHz.
This does not work well for 98% of the end user workloads. Hence my 'botique' comment. SGI and others have made these though in the past, and notice that they don't exist anymore. The market has really dried up.
Thinking forward into 2007 and 2008. If the 'core war' that is going on between AMD and Intel continues. It would be conceivable that we could have a system with two physical sockets on it, but 16 cores. Unless someone changes how we program now for threading it's gonna make the software guys cringe. Clock speed was like crack. It's gonna take a long time for the software guys to get off the crack in regular applications. Sure there is always a specialized application that does really well on humongo number of threads, but Photoshop, Microsoft Word, Mac OS X, Linux, many things don't know what to do after about eight to sixteen cores.
I feel that the comments about systems being out of date will continue because Intel and AMD are going to be fighting their way to the 'top' for the next few years like the did in the late 90s that drove us from 400MHz to GHz in record time.
