OTOY Forums

yes, thats right. You should try with the 470. It should work.

rushes wrote:yes, thats right. You should try with the 470. It should work.

Do you mean buy a 470? That costs money…

mmm so have you bought a 480 without know if it will work?

In fact the 480 had to be installed in another PC… unfortunetly, this other PC has a ram issue

I have just installed windows 7 native in my macpro, whithout bootcamp. Ill try to get soon a 470, hope someone could confirm that it will work.

Did you end up trying the 470 in your 2008 macPro? I am in the same boat and is thinking about doing the same thing (running win 7 x64 and do not care that the card will not be recognized on the osX side). Sure would be nice if I could keep the 8800 in there and put the 470 just for win 7 and octaneRender.....

Would love to hear where you landed on this.....

Thanks,
/Christian

I went through all of this, and I just now booted up my Mac Pro with a GTX 470 for the first time and it is working fine. Any card that works under windows will work in the mac pro, though there are varying amounts of work required to make it happen. The 480 will work as well. The issue isn't that the cards don't fit, (a pcie x16 is a pcie x16 regardless of your OS) the issue is power. Depending on your model it is very hard to access the PSU in a mac pro (though, really, it's no picnic with any of them), so there is auxiliary power for graphics cards located on the mobo (in the 4,1 which i have, they are in the lower left corner when you look in.) But each of the connectors are 6-pin pcie, and they are mac connectors, which means they are smaller than their pc counterparts. I got the 470 because it only requires 2 six pins to power it, so I bought two of the mac power cord converters (you can get them on ebay for 10-20 bucks, type in "mac pro 6-pin pcie connector" and you should find them). So the 470 seemed like the best performance to difficulty ratio.

The 480 on the other hand require a 6-pin and an 8-pin connector. BUT, eight pin connectors were designed to accommodate their 6-pin predecessors, so graphics cards detect what has been plugged in and act accordingly. What "accordingly" is however is different for every card. 6 pins are rated to 120 watts and 8 pins 150 (or something, you get the point), but each actually can carry much more than that. The two extra pins on the 8 pin are actually both grounds, I'm not an electrician, but I gather this means that the same amount of current COULD be pushed through the six pin as the eight, but the eight has less resistance and is therefore safer at higher wattage. So some cards will push more current through the six, some will run on less power, and therefore run more slowly, and others will just not work. Different for every card and you'll just have to do some reading to find out what the deal is for yours (I don't know what the 480 does). You can also get a y-splitter which will allow you to plug a six pin auxiliary into an eight pin connector, bypassing protocol and drawing full power, but it will draw more power than the connector is rated for, so you do so at your own risk. I read someone split enough cables off the mac pro mobo to get two six pins, and two eight pins (enough power for a pair of gtx 480s) off their mac pro's 2 six pin pcie ports and everything booted up and ran, but that just sounds terribly quixotic. Too much power draw and you can melt the connectors, and then you have nothing.

If you really wanted to get that much power going for 2 gtx 480s, you can actually pull extra power off of the empty optical bay using a molex to pcie converter, or you can piggy back an extra psu onto the system like people do on PC's. I don't know much about that last two things, but suffice it to say, if you can run the card in windows, you can run it on a mac in windows but sometimes its a lot of hassle.

All of this comes with one caveat, which is that I haven't gotten octane up and running under windows yet, but as soon as I figure out which cuda drivers I need for windows I'll be doing that. (The video for windows installation says you need "the absolute newest available drivers" but I installed the newest drivers when I did this on the mac side and it wouldn't work until I got the 3.0, and not the 3.1 drivers. Same story for windows? Or is the video to be taken at its word? Not to hijack the thread, but.... anyone?)

Having spent the better part of my day fixing broken partitions, and battling drivers (not used to windows) I can tell you that I have Octane running on my Mac Pro using a gtx 470. The GT 120 runs the monitor and the 470 does the rendering. It seems to be working really well so far. It's not that loud, it is pretty hot though (seems to settle in around 86 C with octane going, I don't really have much context as far as that goes). And if anyone is curious, the 470 gets 22-24 megasamples/sec against the gt 120's ~2.3 megasamples/sec, using the spaceships demo scene without changing anything after loading it. Hope this helps.

That sounds promising. Think I am leaning towards the gtx 460 (2GB) as this seems to be a good value with lots of RAM to boot.

It's specs shows 100 W less (450) than the 470 (550). I would think that the 2008 Mac should be able to handle this? I mean you could order it with 4x cards when it came out. It also has 2x 6pin connectors.

I am still a little unclear on how to connect the card up, I guess I will search for "mac pro 6-pin pcie connector". If you have any other resources or how to's they would be appreciated.

I got Octane (demo) up and running on Win 7 64 bit using the 8800. I had to go to windows update and found an Nvidia driver update under the Optional installs. I ran it and afterwards installed the Cuda toolkit. Octane Render came up just fine after this.

Thanks,
/Christian

thomasbosley wrote:I went through all of this, and I just now booted up my Mac Pro with a GTX 470 for the first time and it is working fine. Any card that works under windows will work in the mac pro, though there are varying amounts of work required to make it happen. The 480 will work as well. The issue isn't that the cards don't fit, (a pcie x16 is a pcie x16 regardless of your OS) the issue is power. Depending on your model it is very hard to access the PSU in a mac pro (though, really, it's no picnic with any of them), so there is auxiliary power for graphics cards located on the mobo (in the 4,1 which i have, they are in the lower left corner when you look in.) But each of the connectors are 6-pin pcie, and they are mac connectors, which means they are smaller than their pc counterparts. I got the 470 because it only requires 2 six pins to power it, so I bought two of the mac power cord converters (you can get them on ebay for 10-20 bucks, type in "mac pro 6-pin pcie connector" and you should find them). So the 470 seemed like the best performance to difficulty ratio.

The 480 on the other hand require a 6-pin and an 8-pin connector. BUT, eight pin connectors were designed to accommodate their 6-pin predecessors, so graphics cards detect what has been plugged in and act accordingly. What "accordingly" is however is different for every card. 6 pins are rated to 120 watts and 8 pins 150 (or something, you get the point), but each actually can carry much more than that. The two extra pins on the 8 pin are actually both grounds, I'm not an electrician, but I gather this means that the same amount of current COULD be pushed through the six pin as the eight, but the eight has less resistance and is therefore safer at higher wattage. So some cards will push more current through the six, some will run on less power, and therefore run more slowly, and others will just not work. Different for every card and you'll just have to do some reading to find out what the deal is for yours (I don't know what the 480 does). You can also get a y-splitter which will allow you to plug a six pin auxiliary into an eight pin connector, bypassing protocol and drawing full power, but it will draw more power than the connector is rated for, so you do so at your own risk. I read someone split enough cables off the mac pro mobo to get two six pins, and two eight pins (enough power for a pair of gtx 480s) off their mac pro's 2 six pin pcie ports and everything booted up and ran, but that just sounds terribly quixotic. Too much power draw and you can melt the connectors, and then you have nothing.

If you really wanted to get that much power going for 2 gtx 480s, you can actually pull extra power off of the empty optical bay using a molex to pcie converter, or you can piggy back an extra psu onto the system like people do on PC's. I don't know much about that last two things, but suffice it to say, if you can run the card in windows, you can run it on a mac in windows but sometimes its a lot of hassle.

All of this comes with one caveat, which is that I haven't gotten octane up and running under windows yet, but as soon as I figure out which cuda drivers I need for windows I'll be doing that. (The video for windows installation says you need "the absolute newest available drivers" but I installed the newest drivers when I did this on the mac side and it wouldn't work until I got the 3.0, and not the 3.1 drivers. Same story for windows? Or is the video to be taken at its word? Not to hijack the thread, but.... anyone?)

what version of OSX supports the new fermi cards from a driver point of view ?

Radiance