Power Mac G4 MDD - BFG 7800 GS OC - did I flash right??

Discussion in 'PowerPC Macs' started by DriesV, May 10, 2013.

  1. DriesV, May 10, 2013
    Last edited: May 10, 2013

    macrumors newbie

    May 10, 2013
    Hi there,

    A looong time ago (mid 2009) I bought a BFG 7800 GS OC graphics card off eBay that I was planning to install in the Power Mac G4 MDD (fully original, unaltered 1.42 DP) that I bought around the same time too.
    I knew I was going to have to flash the card in a PC and alter the AGP-slot contacts to make it work. Somehow, it had been laying on some shelf for almost 4 years. Until yesterday...;)

    I have succesfully flashed the card using this (unaltered) ROM from themacelite.wikidot.com:
    "GeForce 7800 GS generic (nvflash, gotoh), tmeperature sensor removed for G4 running Leo (gotoh)"
    I taped over pin 3 & 11 of the AGP-connector and put it in my mac. At the time of the upgrade this mac had a Radeon 9000 and was running Mac OS X 10.5.8.
    The card was working right away!;)

    However, I'm a little concerned about possible heat issues. When I flashed the card in the PC the fan of the 7800 GS was BLAZING! Now that the card is flashed and running in my mac that same fan is nowhere near as loud. Obviously because of the ROM that I used I cannot check the temperature. So I'm really concerned that the card might actually be overheating.
    note: right after powering the mac on, I can hear the fans (both system fan and 7800 GS fan) blowing at full speed. However, on booting Mac OS X Leopard the fan speed of the 7800GS drops a lot. I cannot even distinguish it over the system fan noise.

    Here's my set of questions:
    • Is this fan behavior as expected for this ROM in Mac OS X Leopard?
    • How can I check whether the full potential of the card is being used? Are there benchmarks, games... with scores of flashed 7800 GS cards in G4 MDDs that I can compare with?
    • Would a different ROM be able to handle the fan differently?
    • Is there a better ROM for BFG 7800 GS OC than the one I used? (for use in a Power Mac G4 MDD, running Leopard)

    The card IS doing its job. I tested some game demos (Halo, Quake 4, Doom 3) and they run fairly well and all expected graphical effects (f.i. advanced pixel shading) are there. It's just that the fan on the 7800 GS never increases on heavy loads. It's at constant (pretty low and noiseless) level.

  2. macrumors 65816


    If you are worried about overheating, you should reflash with the ROM that has temperature detection.

    If you do not know the temp then you cannot know if it is overheating.

    A few minutes longer on boot is nothing compared to a fried card.
  3. thread starter macrumors newbie

    May 10, 2013
    Yeah, that makes perfect sense. Will do!;)
    btw, what's a safe temperature range for these 7800 GS cards?

  4. rabidz7, May 10, 2013
    Last edited: May 10, 2013

    macrumors 65816


    -250-75(no worries) 65-75(a bit too warm, something is slightly wrong if this is idle) 75-90(A little hot, but normal if something very intensive is being done, something is very wrong if this is idle. 90-100(too hot, but ok for a few hours, but not all time, 100-110(SHUT DOWN FROM MENU). 110+(PULL THE CORD OUT BEFORE SOMETHING GETS FRIED)
  5. DriesV, May 10, 2013
    Last edited: May 10, 2013

    thread starter macrumors newbie

    May 10, 2013
    Hhmm...Did I just brick my 7800 GS?:rolleyes:
    I took the card from my mac, removed the taping from pin 3&11 (got a bit peeled off from pulling it out) and re-installed it in my PC, along with a PCI graphics card.
    I had the sensor-enabled ROM and nvflash 5.63 ready on a floppy.

    Using the "nvflash --check" command I saw the 7800 GS listed (index 0).
    When I tried to flash the 7800 GS with this ROM (using the command outlined in the macelite wiki) I got the following message:
    "exiting due to signal SIGSEGV
    General protection fault at ...(et cetera)"
    This happens before nvflash asks for confirmation to flash.
    It just returns to prompt.

    I thought I maybe did not properly seat the card, so I powered off the PC and reseated the card.
    When I then power my machine back on, I just get a blank screen. I get no display from the PCI card. The PCI card displays when I remove the 7800 GS.
    Maybe the issue is that my PC gives priority to the AGP slot for video. However, in the BIOS (crappy, crippled, austere HP BIOS...) I cannot set video priority when only one card is inserted. I can only set priority to PCI (or AGP) when both a PCI and AGP card are inserted. I think my PC is defaulting to AGP. Obviously because of flashing the 7800 GS I cannot get it to display on PC.
    So for the moment I'm stuck.:)

    I think the only solution would be to try flashing on a decent PC, with a proper BIOS that would let me set absolute video priority.
    I think I'm just going to let this 7800 GS go. Not worth bothering much as I wouldn't game with it anyway...
  6. macrumors 6502a


    Apr 25, 2012
    Well for that G4 7800GS is totally overkill because the cpus's cannot provide enough data for the 7800gs to realize its full potential :) of course because it is old technology prices for 7800gs cards are probably so low that it would not cost too much to get a 7800 for old machine like Dual G4...

    I have never bricked card even though I accidentally forced wrong size bios to it, but I guess it is possible to screw up.
  7. thread starter macrumors newbie

    May 10, 2013
    I just taped over pins 3 & 11 again and put the card back in my G4. It works just fine.
    To reflash it with the sensor-enabled BIOS I'd need a PC with a more configurable BIOS that would give boot priority to PCI no matter what graphic card are installed. I'm not going to bother.:)

  8. thread starter macrumors newbie

    May 10, 2013
    I decided to unplug the fan from the 7800 GS and to hook it up directly to the PSU for a constant speed.
    First I tried a 12V to 7V adapter. At 7V the fan speed is about the same as I had once booted into Leopard: quite low. Then I put 12V over the fan. Now the fan is constantly running at full speed. It makes my G4 quite a bit more noisy, but it's till tolerable. At least my 7800 GS is sae now temp wise.


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