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z970

macrumors 68040
Original poster
Howdy. Here's my first troubleshooting post in probably a very long time because I'm officially stumped.

I wanted to pitch this here since I haven't been able to find anything about it anywhere online, and wanted to know if anyone else may have ever noticed this quirk. As the title says, I've got an NVIDIA GeForce 7800 GT installed in my A1117 Power Mac G5, and whenever it is booted into any version of Leopard, it runs normally and the fan is quiet.

But as soon as the system is put into sleep and then woken up, the card's fan continuously runs at full speed and there is no way to reset it without rebooting the machine. Notably, this behavior does not occur in Tiger, where its fan always runs a little faster while idling, but is reliably able to return to the same speed after waking from sleep there as expected.

The card in question is an OEM Mac version (using a blue PCB) and is not a flashed PC equivalent. Furthermore I have verified that this behavior also occurs on stock 10.5.8 as well as Sorbet... meaning it is unrelated to the latter. From what I have seen, there doesn't seem to be anything useful in Console. And the only other things at this point I can think of is perhaps reflashing the BIOS or moving graphics kexts around, but I'm hoping there is perhaps something I'm missing before resorting to such measures.

Has anyone else seen this before?
 
Yes, I have the same card and same behavior. This has also been documented on 68kmla. If you actually let the display (not the entire system) sleep for a second, the fan comes up at full speed and the graphical performance increases drastically (to the same level as it performs out of the box on Tiger without any workarounds). This card seems to have a bug under Leopard.

 
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Well, that explains it. It seems the 10.5.8 NVIDIA kexts are just b0rked. The best solution then will probably be to replace them with versions from previous point releases, one of the Snow Leopard builds, or the ones from 10.4.11.

I wonder if the original 10.5 release had the same problem, or if it was introduced some time afterward?
 
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