Boot problem with GT 120 and GTX 260 installed

Discussion in 'Mac Pro' started by ArthurianLegend, May 6, 2009.

  1. ArthurianLegend macrumors newbie

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    #1
    Recently bought a Nehalem Mac Pro for business and (gaming) pleasure.

    The Mac video card is the standard GT 120. Installed Vista 64 via Boot Camp and installed my old PC 8800 GT in the other 16x slot. Everything worked fine in both OS X and Vista - the mac using the GT 120 and Vista using the 8800 GT.

    Then I ordered a GTX 260 to replace the 8800 GT. Already had the two 6 pin motherboard power leads required to fuel the GTX 260. The problem is that the Mac won't boot now into either OS X or Vista. The startup chime is audible, but then nothing. It's not a fault with the GTX 260 as when I removed the GT 120, it booted into Vista without a hitch. I can't figure out why the Mac won't boot at all when both cards are connected. Tried installing them into different slots too.

    Does anyone else have this configuration (or anything similar) and has got it working? Could it be that the GTX 260 combined with the GT 120 draws too much power when both installed? Taking out the GT 120 each time to play games is not an option! :confused:
     
  2. Tesselator macrumors 601

    Tesselator

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    #2

    I think you might have the answer right there. :)
     
  3. Cindori macrumors 68040

    Cindori

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  4. Tesselator macrumors 601

    Tesselator

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    #4
    "Should" being the key word? Or is that certainty I detect?
     
  5. DoFoT9 macrumors P6

    DoFoT9

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    #5
    serious? i thought the MP had a 1k PSU :-S... ill check the power draw from those cards.

    max of 182W for the GTX260 (min of 550W), and the GT120 can run on a 350w PSU (couldnt find the max usage)

    so even by my calculations 300w + GT120 could never go above 1k. how much do the CPUs use?
     
  6. Pressure macrumors 68040

    Pressure

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    #6
    This isn't about the total amount of watt supplied by the Mac Pro's power supply but rather how many amps it can pump through the 12V and 5V rails.

    There is more to a power supply than the rated wattage.

    For example, the Geforce GTX 260 requires you to have a 500 Watt power supply as minimum if you run a fairly high-end system. But it also requires the power supply to supply (total accumulated) at least 38 amps on the 12V rails.

    I have no idea what the Geforce GT 120 requires.

    Although I am currently running an ATI Radeon HD 2600 XT and an ATI Radeon HD 4890 (32 amps on the 12V rails recommended in a single card configuration) together with no problems.
     
  7. peskaa macrumors 68020

    peskaa

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    #7
    [EDIT: ok, actually read the power leads are plugged in]

    Personally, I think your problem lies with the GT120. I run an 8800GT/GTX 275 setup, and unplug one card or the other depending on what I want to do, essentially disabling it so the Mac Pro can't see it at all. With your setup, both cards are powered and hence the Mac Pro can see both, and gets confused. Got access to a Mac 8800GT (flashed or otherwise) you can try? I've seen 8800GT/260 setups working fine.


    So yes, its not the power problem.
     
  8. DoFoT9 macrumors P6

    DoFoT9

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    #8
    you're completely right, i jumped the gun. sorry
     
  9. 10THzMac macrumors 6502

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    #9
    I do not believe this is a power issue if the board is working OK. I have had an 8800GT AND either a 260 or a 285 running together for some weeks now in two different 08 Mac Pros, and the 8800 needs MORE power than the 120. Could you try removing the 120 and cloning my 8800+260rig? You will need to power the 8800 by routing power from the optical bay but the other recent threads on 285s make it clear how to do this (stick a molex extended on the spare output in the optical bay and temporarily with the case open connect it to one of the molex to 6pin adaptors that probably came with your 260.). Also make sure the 260 is in the **upper slot** and that you are running 10.5.6 and nothing later, with no mods/kexts to try to enable the 260. You should boot from the 8800 under OS X - this will be recognized as a full graphics card and the OS just sees the 260 as a passive PCI device under plain 10.5.6.

    If you have put in hacks to try to enable the 260 under OS X or have installed pre-release OS X you are in deeper water - undo this and check a plain release config first. I have had no end of kernel panics and boot failures under umpteen test configs.

    If you can get the 8800+260 working I would leave it that way. 8800 much better than 120 IMHO!

    This is worrying - it might mean there is something in the 09 firmware compared to 08, or in the 120 compared to the 8800, that is causing a foulup. Or maybe you have a wierd 260 - what brand is it. (I have Zotac 260 and Palit 285).

    If my suggestions do not work it might mean there is some problem with the power connectors on your particular board. If you can borrow a cheap ATX power supply and power all three 6-pin connectors to power the cards you can get a conclusive answer - I had my rig powered this way for several weeks before getting the right cables and grabbing power from the optical bay. But an external PSU should not be needed for this rig. Someone on this forum even has a 295 running off internal power.
     
  10. ArthurianLegend thread starter macrumors newbie

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    #10
    Thanks all for the suggestions. I'm also starting to think that 'boot priority confusion' is the issue. Regardless, I'm also going to double check to see if powering the 260 from another PC's PSU will do the trick. I'm reluctant to try routing power from the optical bay as it doesn't seem very accessible!
     
  11. peskaa macrumors 68020

    peskaa

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    #11
    What slots have you installed in by the way? I have my 8800GT in Slot 2, with the 275 in Slot 1.
     
  12. ArthurianLegend thread starter macrumors newbie

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    #12
    I've tried all kinds of slot combinations - even tried the 120 in the 4x PCI-e slots. When it was working before I installed the 260, the 120 was in the default slot 1 and the 8800GT was in slot 2. I've borrowed a 7300 GT from an older Mac Pro from work to try out tonight - to temporarily replace the 120 and see if it works alongside the 260. May also try hooking up two 6-pin power cables from another PC's PSU to the 260 to try and eliminate that possibility.

    In answer to 10THzMac's question, the brand of card is the Zotac GTX260 216 Core. You may hear it being smashed to pieces if all this is in vain!
     
  13. 10THzMac macrumors 6502

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    #13
    So that is **precisely** the same as one of the cards I have running happily in slot 2 next to an 8800 in slot 1 on my 08 pros.

    On the optical bay access. I decided it was not accessible for some time, and finally pulled harder and it came out. There is then a spare 4 pin molex you can attach (maybe using an extender) to power a 6 pin PCI. But your experiment meantime with an external PSU is fine. Be sure to look up how to fire up a PSU without a motherboard attached. There is some trick sticking a paperclip into two of the pins to fool it into starting outside of a PC. (Sounds crazy but worked fine for me for some time before finally getting at the optical bay).
     
  14. surflordca macrumors 6502a

    surflordca

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    #14
    It's not ony the CPU that draws extra power. Keep in mind all the other stuff. The DVD drive, any USB hubs etc. they all draw power.
     
  15. DoFoT9 macrumors P6

    DoFoT9

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    #15
    hahaha yes im well aware of that.
     
  16. 10THzMac macrumors 6502

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    #16
    mine has two HDs, 16G RAM, FW, USB stuff, DVD as well as the 8800 and 285. I just do not believe this is about power...
     
  17. peskaa macrumors 68020

    peskaa

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    #17
    It isn't about power. The 1000W power supply is enough and more to drive anything you could put in a Mac Pro.
     
  18. 10THzMac macrumors 6502

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    #18
    While peskaa is up, can I ask how far you have got driving your 275 from OS X (any version)?
     
  19. peskaa macrumors 68020

    peskaa

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    #19
    Nowhere. I'm firstly not happy with current power solutions, as both of my SuperDrive bays are full, although I have heard that a spare SATA>PCI-E power may work.

    Secondly, I'm waiting for the "official" 285 release to hit, and hopefully should be useful in enabling other 200-series cards in OS X.
     
  20. ArthurianLegend thread starter macrumors newbie

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    #20
    Finally figured out what the damn problem was! Tried different power routing options (from the drivebay, another PC PSU etc) which made no difference. So power was not an issue after all.

    In case anyone else has this problem, it basically boils down to an incompatiblity between the Zotac GTX 260 and the Apple GT 120.

    To summarise:

    Solely with the GT 120 installed: no problem booting into OS X and Vista.
    Solely with the Zotac GTX 260 installed: no problem booting into Vista.
    Both the GT 120 & Zotac GTX 260 installed: get a startup chime but refuses to boot into either OSX or Vista (despite different power supply configurations).

    When I tried another brand of GTX 260 (a BFG Max Core) it worked flawlessy alongside the GT 120 with the power coming straight from the motherboard molex connectors. I'm guessing that the Zotac ROM and GT 120 ROM don't get along.

    The Zotac is going back to the supplier and I'm getting another BFG!
     
  21. peskaa macrumors 68020

    peskaa

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    #21
    Good choice, mine is a BFG GTX 275 OC, and my PC builds have always used BFG cards.
     
  22. 10THzMac macrumors 6502

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    #22
    We owe you for exposing this problem. I am very surprised indeed given that the 8800 and Zotac 260 (216) were getting along.
     
  23. Pressure macrumors 68040

    Pressure

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    #23
    Couldn't you just flash the card with another ROM and see if that remedies the problem?
     
  24. ArthurianLegend thread starter macrumors newbie

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    #24
    Just when I thought I was out of the woods...got a new issue. This time with the BFG 260. If I cold boot into OS X the fan runs non-stop (at full tilt) and is annoyingly loud! The only workaround I've found so far is by booting into Windows first and then restarting into OS X. If OS X is ever woken from sleep then the fan kicks in again.

    Not yet investigated whether this BFG ROM is flashable, but is there a less risky method of keeping the 260 fan from spinning up - other than pullling out a power cable?
     
  25. peskaa macrumors 68020

    peskaa

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    #25
    AFAIK that problem is caused by a lack of drivers for the 260 - it simply doesn't know what to do with the fans, and hence runs them at full tilt. Beyond pulling power, no solution until we get working OS X support.
     

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