2009 Mac Pro - Radeon 7950 Mac Edition - PCI-E Slot

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Level 1

20 points

2009 Mac Pro - Radeon 7950 Mac Edition - PCI-E Slot

Hi,

So, I have had my 2009 Mac Pro for a while, and it has been a great computer. I have had the original Radeon 4870 the entire time, but since upgrading to Yosemite in 2014, my Mac Pro has become unstable. I often experience my screen freeze up with white squares all over and the only thing that works is my cursor. I cannot do anything else except for hard rebooting the machine. I didn't have this happen initially, but about 2 months after Yosemite, it started all the time.

After a ton of people commenting about similar issues with Yosemite, I came to some conclusions. It had to be that:

My Radeon 4870 was failing slowly
Yosemite has some crappy drivers for my Radeon and other video issues
Or Yosemite had an issue with my 4870 now

I clean installed Yosemite fresh, and for a month I had no issues. I thought I had fixed a software problem. In Feb of 2015 I started experiencing the same freezing again. It started happening and happens more often now.

Hopefully, you are still with me, but what I ended up doing to see if it would fix the issue was to buy the Sapphire Radeon 7950 Mac Edition card. So far, I have had no freezing with it yet, but it is still early on. What my issue is now is now is more of a curiosity.

I got the card the other day, I had the BIOS switch set to Mac, and booted it up. Everything came up fine with the Mac Boot screen. Logged in and About my Mac showed the 7950 fine. However, I noticed the dang card sounded like it was a jet engine. I loaded a fan utility, and sure enough the minimum fan speed was 800 rpm, but this card was sitting at 1300-1500 with no activity. If I started browsing the web, it would take off to 1500 to 1900 rpms. My 4870 never left 800-900 rpm unless I was encoding or doing some heavy work. The temps on the 7950 were fine, so I wasn't sure why the fan was going nuts.

I decided to switch the card from PCI-E slot 1 (where the 4870 always was) to PCI-E slot 2. Well, it works great. It stays at 800-850 rpm unless I do something actually heavy. Card is still a little more noisy at that rpm than the 4870, but it is a lot quieter than 1500 rpm.

So, finally, I wanted to actually ask a question. Has anyone with a 2009 Mac Pro experienced these same graphics freezing issues with Yosemite? Do others have this same fan issue with the Mac 4,1 and the 7950 card? Is this slot thing some kind of fluke or a bug? I don't understand why the 7950 goes crazy in slot 1, but the 4870 was completely fine there.

Just wanted some insight. If the freezing does not come back, I am keeping the 7950, and I assume it will stay in slot 2, since apparently something is wrong with it and slot 1.

Thank you for reading this far and listening! Would appreciate other input. Thanks

Mac Pro, OS X Yosemite (10.10.1), (Nehalem)

Posted on Mar 7, 2015 8:04 AM

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Answer 1

Mar 7, 2015 8:18 AM in response to jasond85

There is a bug with Safari + 10.10.x and also AMD drivers.

The 4870 probably is on endangered species when it comes to 10.10 and it is unable or unwilling I guess to handle newer commands.

Do you have any other PCIe controllers? sometimes they play mischief.

What program reports the GPU fan speed?

Knowing the temperature and fan speed would be nice to know, I need to look at that and keep for reference.

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Answer 2

jasond85 Author

Level 1

20 points

Mar 7, 2015 8:32 AM in response to Community User

So, I keep exploring this issue, and I guess I made a wrong assumption. I was assuming the PCI fan was referencing the GPU card fan, but it's actually referencing the PCI case fan that is in front of the PCI cards.

So, yes, I think there are some software issues. My 4870 seemed to be having some slowness to it since upgrading to Yosemite. I do not have any other PCIe controllers, it is only the 7950 in Slot 2 currently. With the 7950 in Slot 2, the PCI fan in the case stays around 800-850 rpms when not under load, which is just about right in my opinion. The temp is sitting at 37 C when just surfing the web.

I read a forum a minute ago stating that the problem was not the GPU fan, but that the SMC of my mac is calculating the PCI fan speed based on power draw, and it is affected by the power draw of the overall system and what's in slot 1. I guess when I move the 7950 to slot 2, it is ignoring that issue and the fans are quiet. This makes sense, due to the fact that when I used to boot up my Mac from a cold start with the 4870 in Slot 1, it would blast the PCI fan until the startup screen. When the 7950 is in slot 1, it does this and never slows down. When I put it in slot 2, the PCI fan does not blast at all and stays minimum the entire way.

I am under the assumption that I can either just leave the card in Slot 2, or get Apple to fix the SMC firmware to stop that issue. I think I might have to stick with Slot 2. =(

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Answer 3

Mar 7, 2015 8:48 AM in response to jasond85

Reset the SMC when swapping around PCIe cards.

Use FanControl to boost the fans to 850 rpm as minimum.

The SMC will look for temperature sensor reading that says I need to push some air to cool this puppy down, and some GPU like my old 8800GT would also run on startup briefly and is not uncommon in GPUs.

Apple is "done" with SMC firmware updates though. Drivers for AMD 7xxx though do need work.

There are some nice threads on MacRumors and interaction of controllers in Mac Pro that can leave me scratching my head as to what is going on - the order they are loaded during startup, how firmware of each affects others. People that do it for a living still learning.

If you already did an SMC Reset, fine. If not, give it one go, and hit the power button while unplugged.

That, and NVRAM reset from cold boot insures that the system and devices are reset and loaded properly.

If the AMD always acted this way and is new, I would question the seller and others about the GPU fan speed though, it does not sound common or normal.

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Answer 4

Mar 7, 2015 5:47 PM in response to jasond85

when I used to boot up my Mac from a cold start with the 4870 in Slot 1, it would blast the PCI fan until the startup screen

That sound is not the PCI-e slot fan, but the very loud fan on the 4870 card itself. Switch to a 5770 or a different card as the Primary display (that gets initialized at Startup) and the roaring at Startup ceases.

In most cases, the Mac uses measured temperatures inside the chassis -- not power draw -- to determine fan speeds.

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