The Chipset

A very little talked about aspect of the new Mac Pro is the chipset used, which appears to be Intel's 5000X. The only other option is the Intel 5000P, but the 5000P only has x8 PCIe slots off of the MCH and thus it wouldn't make sense given that Apple is only really touting single GPU or multi-display configurations with the Mac Pro.

The 5000X is by no means a desktop chipset, it supports up to four FB-DIMM memory channels and has two independent 64-bit FSB interfaces, one for each Xeon socket. With two FSBs running at 1333MHz a piece, there's a total of 21.3GB/s of bandwidth between the chipset and the CPUs, which matches up perfectly with the 21.3GB/s of memory bandwidth offered if you populate all four FB-DIMM channels on the motherboard. Note that if you only use two FB-DIMMs, you'll only be running in two channel mode, which will limit you to 10.67GB/s of bandwidth. While we have yet to test it, there may be a performance penalty when running in two channel mode.

The 5000X MCH (the "System Controller") supports a total of 24 PCIe lanes, divided into one x16 and one x8. The x8 appears to connect to the ICH (labeled in the graphic above as the "I/O Controller") while the x16 is what drives the primary PCIe slot (the one that has enough room for a double height card).

The ICH have another 12 PCIe lanes coming off of it, and it looks like Apple splits them off into two x4s and one x1 for its remaining PCIe slots. Apple continues to exclusively use physical x16 slots, so each slot can be used by any sort of card (video card or not) rather than having x1 and x4 slots on the motherboard. Because of the Mac Pro's four x16 slots, you can order the system with up to four GeForce 7300GTs for some 8 monitor action.

The ICH used on the motherboard is what we believe to be Intel's 6321ESB and it supports up to 6 SATA devices and 2 PATA devices, which is where you get the expansion capabilities that are built into the system. You've got four SATA hard drive bays and support for up to two SuperDrives. Apple still relies on OS X to provide RAID support, so only RAID 0 and RAID 1 are supported through software.

CPU Analysis Understanding Fully Buffered DIMMs


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  • michael2k - Friday, August 11, 2006 - link

    fb dimms, found in Mac Pros, are fast serial ram using DDR chips. Reply
  • OddTSi - Friday, August 11, 2006 - link

    Perhaps you missed the part where I said "non-ad hoc."

    I know what FB-DIMMs are, but they're more of a band-aid fix or a hack than a ground-up design.
  • michael2k - Friday, August 11, 2006 - link

    Maybe you misused "ad hoc". Ad hoc means unplanned and temporary. Why do you think fb-dimm is a band-aid or a hack? Because the RAM chips themselves are not serial in nature?

    I mean, are you asking "Is there any designs or plans for serial memory chips?"

    To be cost effective you either have to use existing infrastructure, or create a logical evolution/adaptation of the existing infrastructure.
  • AdvanS13 - Thursday, August 10, 2006 - link

    does anyone know apples market segment share for dual processor workstations? Reply
  • peternelson - Thursday, August 10, 2006 - link

    1) I think a gpu swap will need drivers or firmware updating.

    2) To buy a commodity sata drive is good but it MIGHT require the apple carrier in order to fit into the chassis.

    3) You compare apple memory with commodity FBDIMM.
    In the table you quote Apple's UPGRADE (ie on top of base machine) price against the complete cost of the memory. This makes Apple's pricing appear better than it is. Even then it looks like a ripoff, but also consider they are charging you for the base memory in with the basic system price.

  • aliasfox - Friday, August 11, 2006 - link

    As far as I've read, the Mac Pros come with carriers in all four bays - carriers that don't need cables (ribbon or round). Didn't know the backs of SATA drives were similar enough that they could just be plugged in. Reply
  • JeffDM - Saturday, August 12, 2006 - link

    It's not stated in the Anand article, but all drive carriers are included. Apple's Tech Specs page says it, although it could have been more clearly stated. For what it's worth, I think it is worth downgrading the stock drive to 160GB and spending that difference toward additional drives. Going from 250GB to 160GB saves $75, that price difference would buy you a 250GB SATAII drive. Reply
  • JAS - Thursday, August 10, 2006 - link

    It appears that some people managed to receive their Mac Pro quickly.">
  • IntelUser2000 - Wednesday, August 09, 2006 - link">

    Check out the memory bandwidth benchmark. Quad channel is needed to match Core 2 systems' memory bandwidth using only dual channel. Dual channel on Xeon 5100 drops to approximately 68% of the quad channel bandwidth. That in numbers is 3.8GB/sec. Not to mention Xeon 5100 series has 25% higher memory FSB. It needs 25% higher FSB and 2x memory channels to achieve the same memory bandwidth numbers the desktop Core 2's can. According to memory latency benchmarks, the latency is also significantly higher on the Woodcrest than Conroe's platform.

    The chipset on the Xeon 5100 is worse in performance than the chipset on the Core 2. It will NOT beat Core 2 because of the 25% higher FSB, it will rather be SLOWER. Not to mention FB-DIMM makes it even slower.

    SpecFP benchmarks also support this:
    Xeon 5160(3GHz/1333MHz FSB/4MB L2/8x1024MB FB-DIMM DDR2-667): 2775
    Core 2 Extreme X6800(2.93GHz/1066MHz FSB/4MB L2/2x1024MB DDR2-800 5-5-5-15): 3046

    Core 2 Extreme gets almost 10% higher in the memory substem portion of the SpecCPU 2K. benchmark, even though it has 2.2% less clock speed than the Xeon 5160.

    Look here:">

    "ScienceMark didn't agree completely and reported about 65-70 ns latency on the Opteron system and 70-76 ns (230 cycles) on the Woodcrest system. We have reason to believe that Woodcrest's latency is closer to what LMBench reports: the excellent prefetchers are hiding the true latency numbers from Sciencemark. It must also be said that the measurements for the Opteron on the Opteron are only for the local memory, not the remote memory."

    Xeon 5160 got 70-76ns in ScienceMark, what did Core 2 get?? It got 36.75. Xeon 5160's ScienceMark latency is higher than Pentium Extreme Edition 965's latency, and twice the latency of Core 2.

    Everest shows the same thing:">

    Xeon 5160: 99.1
    Opteron 285: 57.7(seems higher than FX-62 results but this system uses Registered DDR DIMM, you can see in AT's results that AM2 further lowers latency)

    Core 2 Extreme: 59.8">

  • dcalfine - Wednesday, August 09, 2006 - link

    Overall, I think this is a very well-designed system, and in price comparisons with Dell, the Mac Pro came out over a thousand dollars cheaper for a similar system. I may be a fanboy, but I can admit that Apple still has some work to do here. As good as the Mac Pro is, I think Apple needs to start having better video options. For starters, the X500 chipset is used, which means that there's only one 16X PCIe lane. Also, Apple should get closer with Nvidia and start working in SLI, as well as FX4500X2 and FX5500. A Vanilla FX4500 just doesn't make the cut anymore. Also, the X500 chipset supports one 133X PCIX slot, which, I think, Apple should have incorporated, since not every expansion card has moved to the PCIe format.

    I'd like to see some speed comparisons between the mac pro and some pcs. I imagine that in most (if not all) test the Mac Pro will come out slightly slower than the PC due to the bells and whistles of Mac OS X, but I'd like to see just how much slower it runs, and how it runs in Boot Camp running Windows/Linux.

    But, yeah. Good goin', Apple!
    And AnandTech, get your hans on one of these ASAP!

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