G5s - spot the difference

Posted:
in Current Mac Hardware edited January 2014
What are the differences between the 1.6 G5 and the other machines in the range? Apple have a history of producing "Diet" or "Lite" versions of a machine at the bottom end, which then disappear at the first revision.



Laying aside the difference in processor speeds, front side bus speeds, stock RAM and hard disk capacities, I know that the 1.6GHz machine features:



PC2700 RAM as opposed to PC3200

Only 4 DIMM slots as opposed to the full complement of 8

4GB max RAM compared to 8GB

PCI as opposed to PCI-X



Are there any other, more subtle differences, like controller chips etc.? Are bandwidths reduced beyond simple frequency variations? And do you expect this stripped-down motherboard to disappear with the first speed-bump?

Comments

  • Reply 1 of 10
    As someone pointed out (cant remember where) the 1.6 G5 motherboard bears more than a passing resemblence to the G4 MDD motherboard. Obviously it has a new controller chip and serial ata (but this was a straight swap for the 2 ATA 66/100 buses) instead but since the G5 came along I have been wondering if this was the m/b Apple started working on with the G5 and then later made the decision to go up to the new stuff (PCI-X, etc) and leave this design as is. You cant help the feeling that this is another Yikes..... I would avoid it at all costs.
  • Reply 2 of 10
    messiahmessiah Posts: 1,689member
    Quote:

    Originally posted by Thereubster

    As someone pointed out (cant remember where) the 1.6 G5 motherboard bears more than a passing resemblence to the G4 MDD motherboard. Obviously it has a new controller chip and serial ata (but this was a straight swap for the 2 ATA 66/100 buses) instead but since the G5 came along I have been wondering if this was the m/b Apple started working on with the G5 and then later made the decision to go up to the new stuff (PCI-X, etc) and leave this design as is. You cant help the feeling that this is another Yikes..... I would avoid it at all costs.



    Yeah, that was what I was worried about - a Yikes! MKII. MacUser UK reckoned that the 1.6 had essentially the same motherboard as the G4 MDD, whereas the other models got the newer, re-designed motherboard.



    We had a Yikes! in the studio for a while and there were a number of annoying little limitations that surfaced during it's use. Like the inability to boot from an external FireWire volume. These things were never mentioned in the sales literature, and only surfaced during extended use. I wonder if the G5 1.6 will also have little inconsistencies?
  • Reply 3 of 10
    thttht Posts: 3,226member
    Quote:

    Originally posted by Messiah

    What are the differences between the 1.6 G5 and the other machines in the range? Apple have a history of producing "Diet" or "Lite" versions of a machine at the bottom end, which then disappear at the first revision.

    ...

    Are there any other, more subtle differences, like controller chips etc.? Are bandwidths reduced beyond simple frequency variations?




    The 1.6 GHz motherboard is identical to the 1.8 and 2.0 motherboards in size and shape, but differs in the aforementioned areas. It doesn't have the second CPU slot, even though the motherboard area is there for it. It doesn't have the extra RAM slots even though the motherboard area is there. It appears all Apple did was not install those slots, sockets and associated PCB traces during manufacturing.



    It uses the exact same set of chips. Same system ASIC, same I/O ASIC, and probably the same exact Hypertransport PCI/PCI-X tunnel chip but is only set to support PCI. The rest is reduced frequencies on buses.



    This is totally different from the Yikes motherboard which used a different system ASIC and did not support AGP. The Yikes board was the previous generation Power Mac G3 motherboard and ran the G4 CPU on a 60X processor bus.



    Quote:

    And do you expect this stripped-down motherboard to disappear with the first speed-bump?



    I'm hoping it becomes the motherboard for a prospective G5 mini.
  • Reply 4 of 10
    thttht Posts: 3,226member
    Quote:

    Originally posted by Thereubster

    As someone pointed out (cant remember where) the 1.6 G5 motherboard bears more than a passing resemblence to the G4 MDD motherboard.



    It has zero resemblence to the G4 MDD motherboard. Absolutely zero.



    Quote:

    Obviously it has a new controller chip and serial ata (but this was a straight swap for the 2 ATA 66/100 buses) instead but since the G5 came along I have been wondering if this was the m/b Apple started working on with the G5 and then later made the decision to go up to the new stuff (PCI-X, etc) and leave this design as is.



    The 1.6 motherboard is identical to the 1.8 motherboard with the exception of CPU, bus and memory frequencies and the PCI support in the Hypertransport PCI tunnel chip.
  • Reply 5 of 10
    messiahmessiah Posts: 1,689member
    Wow! Thanks THT!
  • Reply 6 of 10
    thttht Posts: 3,226member
    Quote:

    Originally posted by THT

    The 1.6 GHz motherboard is identical to the 1.8 and 2.0 motherboards in size and shape, but differs in the aforementioned areas. It doesn't have the second CPU slot, even though the motherboard area is there for it. It doesn't have the extra RAM slots even though the motherboard area is there. It appears all Apple did was not install those slots, sockets and associated PCB traces during manufacturing.



    I was at the Apple store today, and got a good look at the 1.6 motherboard, and it looks like the ball solder points for the second CPU socket were there and the pin sockets (or whatever they are) for the 4 missing memory slots were there. So, the PCB traces for the second CPU socket and 4 memory slots were on the board, Apple just didn't install the socket and slots during manufacturing.



    It looks like the only differences between the 1.6 and 1.8 GHz G5 machines are the settings of certain resistors to change bus frequencies, to eliminate PCI-X support in the Hypertransport PCI/PCI-X tunnel, and the 4 other memory slots. The dual 2 GHz motherboard has the second CPU socket installed (and associated resistor settings).
  • Reply 7 of 10
    lucaluca Posts: 3,833member
    That sounds like what UMAX did with the J700. Basically, the J700 had a motherboard identical to the S900 but with two fewer PCI slots (4 instead of 6). All the wiring was there, the slots just weren't in place. Someone managed to put some slots in place and get them working, essentially turning his J700 into an S900.



    Here's the link: http://www.applefritter.com/hacks/me...sis/index.html



    I wonder if anyone would be brave enough to try that with a 1.6 GHz G5?



    Heck, maybe someone could even swap a few resistors and turn their 1.6 GHz G5 into a PCI-X enabled, 1.8 GHz G5 with 8 RAM slots! Pointless though... given the amount of time and effort you'd put into it, you may as well just go for the 1.8 in the first place.
  • Reply 8 of 10
    thttht Posts: 3,226member
    Quote:

    Originally posted by Luca Rescigno

    Heck, maybe someone could even swap a few resistors and turn their 1.6 GHz G5 into a PCI-X enabled, 1.8 GHz G5 with 8 RAM slots! Pointless though... given the amount of time and effort you'd put into it, you may as well just go for the 1.8 in the first place.



    But with a bit of minor soldering, a person can probably turn a 1.6 GHz G5 into a 1.8 or 2.0 GHz G5, or higher, buy cutting and soldering some resistors. It'll only have 4 DIMM slots and 1 CPU, but it can have a 2+ GHz overclocked G5, 1+ GHz processor bus, and PC3200+ memory. That's just a good wire cutter, a good soldering iron, and maybe a resistor or two. Not sure what is involved with asynchronous buses though, or how they are configured.
  • Reply 9 of 10
    lucaluca Posts: 3,833member
    And, of course, there's the risk you are taking by overclocking, and the fact that the warranty becomes void.



    I wonder how high people will overclock their G5s? I remember when the dual 1.0 GHz G4 came out, someone overclocked it to a 1.2 GHz, but that's about all I remember. I wonder how well the G5 would overclock? It generates a lot of heat as it is, but the case is designed to deal with it at least.
  • Reply 10 of 10
    Quote:

    I'm hoping it becomes the motherboard for a prospective G5 mini.



    Amen, THT. I suppose it will never happen. I wish Apple would just come out and say that they will never do a cube/mini-tower/pro-sumer model/headless iMac because:



    A. It would impact Power Mac sales

    B. It would impact iMac sales

    C. Today's chips are too hot

    D. Profit margin would be too low

    E. We don't want to admit to all you "Power Macs are too $" crybabies that you had a point.

    F. Other



    Then, at least, I wouldn't hold out false hope.
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