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


View All Comments

  • vladik007 - Wednesday, August 09, 2006 - link

    Flashing PC video cards to work on G5 was possible and in my own experience also rock solid. I have 2 G5;s at home ( one 2.0Ghz very 1st released ) and 2.7ghz. PNY 6800 GT with 2120 firmware has worked for over a year now and ZERO crashes in that time in both of them.

    So if PC videocards will NOT work in Mac Pro by just simply sliding in , firmware flashing will.
  • ViRGE - Wednesday, August 09, 2006 - link

    Anand, has Apple/Nvidia/ATI commented on what video card compatibility will be like with the Mac Pros over the PowerMacs? With the PowerMacs, PC video cards were incompatible due to OpenFirmware and more importantly endian issues. The Mac Pro however is EFI and not OpenFirmware, and there are no endian issues, which gives everyone a lot of hope that the system may be able to take on vanilla 7900's and the like.

    Has anyone said anything on this matter going one way or another?
  • blwest - Wednesday, August 09, 2006 - link

    I'll know tonight when I try to slap my 7800gt into the box! Reply
  • artifex - Friday, August 11, 2006 - link

    He never came back... maybe he blew up his new Mac Pro? Reply
  • archcommus - Wednesday, August 09, 2006 - link

    Given that this hardware is just like a PC and 100% x86, and given that the new OS X is designed to run on that hardware, what is REALLY the obstacle in getting OS X to run on our own Windows and Linux machines? Reply
  • Missing Ghost - Monday, August 14, 2006 - link

    yep OSX does not use the bios. It needs efi Reply
  • AaronAxvig - Wednesday, August 09, 2006 - link

    They still have the EFI boot system, no? Reply
  • mrgq912 - Wednesday, August 09, 2006 - link

    Back when Apple made they announcement that they were going to switch from power pc to intel cpus. I thought why intel and not amd? Now it seems that Intel must have shown them what their new hardware is capable of, and Apple didn't even need to think twice about the move. Good call by apple.

    But I still won't buy closed system like Mac pro.
  • hmurchison - Thursday, August 10, 2006 - link

    Please don't take offense to this but that was really a silly statement. Back in the days when you had differing hardware between Macs and PCs you could say the Mac was more closed. Nowadays you have the ability to run OS X, Windows and Linux simultaneously and a lot of hardware will just plug and play with the appropriae minidrivers in the OS. Reply
  • mrgq912 - Saturday, August 12, 2006 - link

    none taken. i didn't know that mac pros allowed you to switch video cards and memory. I always wanted to use the mac os for every day use, and have windows for games and such. But now the only thing stopping me is the price. Reply

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