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essenceofwar

macrumors newbie
Original poster
Jan 24, 2013
14
0
Hey,

Quick: I'm getting kernel panics whenever I try to boot into OS X Mavericks with a non-EFI GPU in a PCI slot.

Long:
My GF has an 8-core Mac Pro 3,1 w/ 8 GB of RAM and both a Radeon 2600 XT and a Sapphire Radeon 7950 (non-mac edition!).

Under mountain lion, the GPU upgrade was plug-and-play, no boot screen of coure, of but it worked just fine once the OS loaded drivers and such. I removed the 7950 to upgrade to mavericks, upgraded, booted into OSX, did a back-up, then I shut it down, added the 7950 (w/ appropriate power cables of course) and now I get kernel panics at boot. Verbose boot mode makes it to something like:

"AMD Tahiti Graphics Accelerator in Slot 1/4"

before it reboots and displays the kernel panic screen. Has anyone run into this problem before with an inkling as to how I might fix it?
 
The 2600 XT is in PCI slot 1. The 7950 is in slot 4. I use the 7950 to drive all of my monitors normally, but I keep the 2600 XT in slot 1 in case I have to swap monitor sources to be able to have a boot screen. The 7950 is just a standard non-EFI card so it doesn't allow me to have a boot screen.

Edit: To clarify, the original purpose of the 7950 was to correct for a stuttered video playback problem under Mtn Lion with the 2600 XT.
 
Last edited:
The 7950 has 2x6pin power connectors and I have one of those apple-mini-6pin to-2x-regular-pci-6pin converters to power it.

I'll give it a whirl and report back.
 
I can't tell 100% if it's kernel panic'ing since I can't get a boot screen w/o the 2600XT, but it sure looks/sounds like it is with the 7950 alone.
 
No worries.

For some inexplicable reason, 3,1s have a habit of running some of their GPUs better/faster in slot 2. Being as only slots 1 and 2 are 16x in 3,1s that's where your GPUs should be.

I was concerned that OS power management had changed significantly in the move to Mavericks, such that the 2600XT 'pushed it over the edge' as it were. Power management has actually been altered significantly in other areas of the OS (Power nap).

Can you confirm that the EXACT same setup worked in ML, but now crashes in Mavericks? With absolutely no other changes?

I'm just trying to get more info to go on.

----------

Have you got two 6pin leads coming from the one socket on the motherboard?

I ask, because they're only rated to 75w and I'm pretty sure the 7950 wants more than that…
 
Have you got two 6pin leads coming from the one socket on the motherboard?

I ask, because they're only rated to 75w and I'm pretty sure the 7950 wants more than that…

To clarify, I have one of these:
http://www.amazon.com/PCIe-Power-Cable-nVidia-Video/dp/B0051PWFCU

which should provide full power to a 7950, because I'm pretty sure that the 7950 mac edition uses the same cable for 2x6pin pci.

Can you confirm that the EXACT same setup worked in ML, but now crashes in Mavericks? With absolutely no other changes?
I was pretty careful about making no other changes. Originally, I tried to do a direct upgrade to mavericks with the 2 video cards that I was running with under ML, but that gave kernel panics at reboot after running the mavericks installer, so I removed the 7950, did the upgrade with just the 2600 XT, and that worked fine, booted to mavericks, etc. The problem comes now when I add the 7950 to make the exact same configuration I was running with under ML, now I get kernel panics at boot.
 
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You should not be using a Y-Cable for power. You need two cables.

Really? I just thought that the mini-6pin connectors on the Mac Pro logic board could each provide up to 150W. Was I totally mistaken?

At any rate, it's only a couple of bucks to pick up the correct power cables, do you think this could be the source of the problem, even though I've been running with the other power cable under Mtn Lion for ~ 6 months?
 
Really? I just thought that the mini-6pin connectors on the Mac Pro logic board could each provide up to 150W. Was I totally mistaken?

At any rate, it's only a couple of bucks to pick up the correct power cables, do you think this could be the source of the problem, even though I've been running with the other power cable under Mtn Lion for ~ 6 months?

Nothing in this world is guaranteed, but if we take care of the obvious first…

As I said/wrote above, each socket on the 3,1s motherboard is rated at 75w for a 150w total - running two plugs from one socket, there's a mild, but real risk of burning a trace on the motherboard - not good. So best to run two cables, one from each motherboard socket.

The kind of shutdown you describe is very reminiscent of the type you get when one accidentally forgets to plug in the powercables after refitting the graphics card - Shall we just say this type of shutdown is not unknown to me - neither is the act of the facepalm following the realisation :p

The actual drivers for the 7950 are built into Mavericks so it should 'just work' - if it doesn't - check the power - else check for physical damage - otherwise it's borked, in which case I'd be having a word or two with whoever sold it to you.

If you *do* want boot screens on your card, I vaguely recall there being something about it on Netkas' forum http://forum.netkas.org

I know I've flashed lesser PC cards following tutorials on Netkas'.

Just in case you think we may be being pernickety… alot of the experience being imparted here has been learned the expensive, hard way - and if spending 7 or 8 bucks on another powercable saves you a hundred or more….
 
The actual drivers for the 7950 are built into Mavericks so it should 'just work' - if it doesn't - check the power - else check for physical damage - otherwise it's borked, in which case I'd be having a word or two with whoever sold it to you.

Yeah, that's what I was expecting, same sort of deal as per Mtn Lion. Since the card still worked under Mtn Lion, I'm going to figure that the card is PROBABLY ok, at least for now, and go for the least expensive potential solution, and try to get the correct power cables. I feel really dumb for not sorting this out originally.

Just in case you think we may be being pernickety… alot of the experience being imparted here has been learned the expensive, hard way - and if spending 7 or 8 bucks on another powercable saves you a hundred or more….

I know, I'm very grateful for the advice. I'm pretty persnickety myself where it comes to my own areas of expertise in PC hardware, but my GF only turns me loose on her hardware when there are problems, and I tend to have all sorts of gaps in my knowledge WRT things I didn't put together myself :eek:
 
Ugh, so I replaced the power connector that I mentioned previously with 2x mini6pin to pci 6pin cables like ActionableMango linked to above. So I now have a cable on each of the motherboard headers running to each of the 6pin slots on the 7950.

I'm seeing exactly the same behavior. Anytime the 7950 is in the system, it kernel panics at boot, anytime the 2600 XT is in alone, it boots into Mavericks w/o any trouble.

Is it possible that I've burned out MoBo traces or damaged the card? It seems so strange since they were all working w/o any problems in Mtn Lion.
 
One way you can tell is if you have a spare HDD and can do a clean install of/revert to Mountain Lion & see if it still works with the older OS. If it does there's a solid chance the card is OK, but means you'll need to dig deeper for a solution. If ML also crashes now though, then I'd say it's fairly likely that some hardware has gone T-U. Which hardware though becomes the question at that point, and hopefully it's the cheaper of the two between video card & logic board...
 
Ugh, so I replaced the power connector that I mentioned previously with 2x mini6pin to pci 6pin cables like ActionableMango linked to above. So I now have a cable on each of the motherboard headers running to each of the 6pin slots on the 7950.

I'm seeing exactly the same behavior. Anytime the 7950 is in the system, it kernel panics at boot, anytime the 2600 XT is in alone, it boots into Mavericks w/o any trouble.

Is it possible that I've burned out MoBo traces or damaged the card? It seems so strange since they were all working w/o any problems in Mtn Lion.

I'm not ignoring your plight - I'm thinking and researching, I'll be back if/when I find something constructive.

While I'm doing that (!) can you test the card in another machine at all?

Also, can you pop the 2600XT back in and grab as many details of the failure to boot as possible from the verbose booting screen. When it crashes and attempts to reboot, press and hold the power button to stop the machine coming back up again. Take out the 7950. Reboot, and you should get an error message, something along the lines of your Mac did not shut down properly, or somesuch, with 'report' or 'ignore', try clicking report and see if it shows you the report before sending it off, if so, see what you can glean from it save a copy too if possible.
 
So I ended up selling the 7950 (which appeared to be working fine when I tested it in my gaming PC) and picking up Sapphire 7950 from OWC, but I'm still running into problems.

I boot just fine with the new card, but no signal is ever sent to either of the displays (one via MDP, one via DVI). I can tell because if I leave the 2600 XT in, I'll happily get to a boot screen on the display attached to the 2600 XT, but the display attached to the 7950 will never show anything.

I've tried:
1) Checking the power cables, I get an audible click both at the logic board connector and at the GPU connector, so that should be OK.
2) I've reseated the GPU several times, and it's firmly in place.
3) I tried installing drivers before adding the new GPU but OSX told me that it already had all drivers for my device included.
4) Booting w/o the 2600 XT results in no image to either display.

I'm pretty confused again:confused:

EDIT:

On a lark, I tried another thing and everything appears to be working. Apparently one of my displays was having a fit about having two inputs connected to it, even though one of the inputs was connected to nothing. Everything appears to be in order finally! :)
 
Hi
I saw your post when search for answer to my same problem. When I install 7950in Mac Pro running 10.9.2 the machine crashes at booting and go in a loop.

May I ask how did you finally solve this problem?

Thanks
 
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