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My GPU only fits in slot #2 of my 1,1 Mac Pro... how can I run it at full speed?

PowerMac G4 MDD

PowerMac G4 MDD

macrumors 68000
Original poster
Jul 13, 2014
1,900
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So, long story, but I installed an Arctic Accelero S3 passive GPU cooler on my Radeon 5770; the thing is massive, but it's able to silently keep this thing cool, instead of my having to deal with its noisy fan and plastic enclosure...

Sadly, it has heat-sink hardware attached to the bottom and top faces of the card, which means it cannot fit in the first PCI slot. When I booted the Mac up, Expansion Slot Utility popped up and told me that my card is not running at full speed, as it's not detected in the 1st slot.

Is there some way to configure this so that the second slot is my primary slot? I'd like to use my card to its full potential, while it sits here in this second slot.

-Thanks (I have never even seen Expansion Slot Utility before, so I'm unsure as to whether or not there's a preference for this type of thing.)
 
Yes, see attached.

Lou
2wxUcP.png
 
h9826790 said:
Better to choose option 3 because there is no way that you can use slot 3 with that heat sink.
Click to expand...

Just tried option 3 and restarted, but it still says that my card is running below maximum speed.
 

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Don't worry, I run my 2nd GPU (7950) in a x4 PCIe 2.0 slot, just 4% performance hit (compare to the same GPU in slot 1). The actual penalty is negligible.
 
h9826790 said:
Don't worry, I run my 2nd GPU (7950) in a x4 PCIe 2.0 slot, just 4% performance hit (compare to the same GPU in slot 1). The actual penalty is negligible.
Click to expand...

It could just be in my head, but I felt like certain graphics/animations felt slower than usual. I'm unsure as to whether this happened previously or not, but an example would be the 'More Info' menu in 'About this Mac.' (I'm referring to the modern one, not simply System Profiler.) When I switch between the tabs it has, the animations are at a very low frame rate. However, when I played Minecraft, I noticed that my FPS remained the same, so who knows?

Sadly, I already went and removed the bottom heat-sink from my card's cooler, leaving the main heat-sink alone. Due to the cheap screws/horrible screw design of this Arctic cooler, I snapped two screws; half of them didn't even go all the way in in the first place. I actually made a video about that:

Now I gotta go to the hardware store and find replacements with my own design. After all this trouble, I may stick with my original plan of leaving the bottom heat-sink off and finally being able to put this card into slot #1. I hope my card doesn't fry. I can't judge my card's temperature in Mac OSX, but should I be concerned if, with both heat-sinks on, the card (under heavy load) was too hot to rest my finger upon for more than a few seconds? (I'm talking about the metal side of the card, which is a bezel that connects to a built-in RAM-chip heat-sink for the card... I suppose that that is why it's so hot.)
 
i have been down this road before. if the screws stick down and have springs it is possible that they will hit the bottom plate and push the heatsink up over the GPU core, causing it to overheat.

I ended up buying taps and dies to try to make some of these work. Also smaller screws, this also proved difficult, I still have some cards in the "unsold" bin for this reason. I have never understood why some PC cards have screws sticking 1/4" or 1/2" into next cards space. I guess they [planned on those giant old PC towers with acres of empty space but why limit your cards usage like that?

Good luck.
 
MacVidCards said:
i have been down this road before. if the screws stick down and have springs it is possible that they will hit the bottom plate and push the heatsink up over the GPU core, causing it to overheat.

I ended up buying taps and dies to try to make some of these work. Also smaller screws, this also proved difficult, I still have some cards in the "unsold" bin for this reason. I have never understood why some PC cards have screws sticking 1/4" or 1/2" into next cards space. I guess they [planned on those giant old PC towers with acres of empty space but why limit your cards usage like that?

Good luck.
Click to expand...

The screw actually wasn't too long, but what they did was put components of the GPU cooler right underneath the holes.
They must have not thought that through when they were building it. (The reason is because certain cards use certain holes on the bracket. Only some of the holes line up directly with the copper piping or other metal components.)
 
MacVidCards said:
i have been down this road before. if the screws stick down and have springs it is possible that they will hit the bottom plate and push the heatsink up over the GPU core, causing it to overheat.

I ended up buying taps and dies to try to make some of these work. Also smaller screws, this also proved difficult, I still have some cards in the "unsold" bin for this reason. I have never understood why some PC cards have screws sticking 1/4" or 1/2" into next cards space. I guess they [planned on those giant old PC towers with acres of empty space but why limit your cards usage like that?

Good luck.
Click to expand...

The hardware store definitely didn't have screws like this, so I have to wait until a local computer store's technician is in on Tuesday. Like you mentioned, I need to look for screws that don't stick out too far from the underside of the card, as that, too, would keep my card from fitting in slot #1. One issue, though: I want a screw with a nut that can be tightened from the underside of the brackets that hold this Arctic heat-sink into place. However, if I were to put those screws in first and tighten them, I obviously wouldn't be able to put the card on then, as the screws have heads on them. I may have to look for screws with no heads, tighten them to brackets in that same fashion, and then find some caps that can secure the card to the brackets/screws without sticking out too far and keeping the card from using the 1st PCI slot. I can't imagine finding nuts/caps that small, though. I'd have to find screws that don't stick out too far, and then caps that are THAT thin. Looking at the Mac Pro, I can see that the card almost touches the top of the memory cage... that will be one tiny screw cap, eh? I hope I can pull that off.
 
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