GTX 285 vs 2 X 4870 in crossfire

[Abidubi]

Ok, I need some help getting some facts straight. I am considering upgrading from the 4870 to the 285. It's a fine idea except that the 285 is very expensive, but at least I could try and sell the 4870 and maybe get $300CAD for it. Then I thought, what about just getting a second 4870 and crossfiring them? I have read through a good 3 or 4 threads on these forums about powering the second card, flashing PC cards and working with crossfire... that was a freaking long 3 hours of reading non-stop.

So I have these questions which I hope someone here can answer with reasonable certainty.

1) When doing crossfire, do the cards have to be very similar for them to work? If 1 card is 512 and the other 1GB will there be any advantage over just getting a card with 512?

2) If other cards of the same family work, would a crossfiring of the apple 4870 with a 4870X2 perform similar to 3 X 4870 in crossfire?

3) Could someone explain the cables and/or hardware needed to power the second card from the second optical drive slot? I think the best way to go is 1 cable from each card to the regular spot and 1 cable from each card going to the same connector in the optical bay.

4) Apparently 2 X apple 4870s don't work with crossfire. But does this apply to combining an apple 4870 with an unflashed PC 4870?

5) I thought I read about some attempts to modify the ROM of the apple card to enable crossfire with some success. Is that true and if so where is this ROM and does it negatively impact the apple 4870 in OSX?

6) If have read in the past (I think with the PC 3870s) that if you connect a second unflashed card to an apple card with the crossfire link that the card behaves in OSX (doesn't spin it's fans wildly). I don't need it to do anything in OSX except not blow up, I only care about it working in windows. I'd like to avoid flashing the PC card if I can.

Thats about all I can think of for now. Thanks for the help.

[gzfelix]

Mac OS X simply doesen't support CrossFire.

[Abidubi]

Mac OS X simply doesen't support CrossFire.

"I don't need it to do anything in OSX except not blow up, I only care about it working in windows. I'd like to avoid flashing the PC card if I can."


Oh and I just had 2 jets (F-18 or something else, couldn't see them) do a full afterburner take-off over my house... love when those bastards do that, house rumbling and all.

[MattZani]

2 4870's will be alot more powerful than a 285.

I Think if you have a Apple 4870 and a PC 4870, in OS X the PC wont do anything, and in Window, the Apple will work normally with the PC.

[Nugget]

With all the reported driver problems people seem to be having I'd suggest staying far away from the 285. For now, at least. The EVGA Forums (http://www.evga.com/forums/tt.asp?forumid=87) are full of dissatisfied mac users. Kernel panics and flaky drivers that don't allow the card to work at full speed in OS X.

[Abidubi]

Anyone have good answers for #4,5 and 6?

[Tallest Skil]

CrossFire isn't possible in OS X. Period.

CrossFire works with Apple cards in Windows, I believe.

If you're using PC cards, don't screw with the ROM. Just install netkas' injector.

[The Rominator]

As Mathew Russo and I were discovering, the Crossfire support is TURNED OFF in Apple's ROM.

There is NO WAY to use an APple 4870 in Crossfire without flashing it...once done it will be SECOND card in Crossfire, not first. (So, no good with 24" LED ACD)

Read our efforts ...not sure where but you can find.

The GTX285 issues are overblown, and bound to improve, as the 8800GT did with time.

[Abidubi]

As Mathew Russo and I were discovering, the Crossfire support is TURNED OFF in Apple's ROM.

There is NO WAY to use an APple 4870 in Crossfire without flashing it...once done it will be SECOND card in Crossfire, not first. (So, no good with 24" LED ACD)

Read our efforts ...not sure where but you can find.

The GTX285 issues are overblown, and bound to improve, as the 8800GT did with time.

I had been following your posts. I wasn't too sure whether you meant 2 apple 4870s didn't work or any combination involving an apple 4870.

What do you mean once you flash the apple card it will work as the second card? Will it no longer work in OSX? Are you no longer able to run a display off of it?

If it means I can't run a display off of it, can I connect the display to the PC card and it will still produce an image in OSX?

[Bubba Satori]

Stop it. Steve doesn't want you fiddling with video cards. :D

[Topper]

With all the reported driver problems people seem to be having I'd suggest staying far away from the 285. For now, at least. The EVGA Forums (http://www.evga.com/forums/tt.asp?forumid=87) are full of dissatisfied mac users. Kernel panics and flaky drivers that don't allow the card to work at full speed in OS X.

Vocal minority. Some people like the GTX 285. (http://www.evga.com/forums/tm.asp?m=100785469)

[Nugget]

Well if I had all those problems you can bet I'd be vocal too!

[Chad H]

My MP is fixing to get an overhaul. I'm throwing my GTX285 back in with 2 corsair 64GB SSD's and they will be in RAID 0. I will have a 3rd corsair for Bootcamp gaming. Also installing 6GB of RAM. But, I will run complete benchmarks so you can look at the GTX285.

[brock2621]

The 4870's require TWO power connectors so there aren't 4 available in the stock mac pro's. You could run splitters but then you're over the limit for the power supply so you are going to need a drive bay power supply to run those things. Lastly, OSX doesn't support crossfire soooooooo.... not worth the extra investment basically.

[Cindori]

Why are you buying a Mac?

[grue]

The 4870's require TWO power connectors so there aren't 4 available in the stock mac pro's. You could run splitters but then you're over the limit for the power supply so you are going to need a drive bay power supply to run those things. Lastly, OSX doesn't support crossfire soooooooo.... not worth the extra investment basically.


I'm not sure I entirely believe that the power supply can't handle it. I have the one of the most power hungry Mac Pro Apple has shipped (2007 8x3.0) with all the RAM slots full, 5 SATA HDDs (one of which is 10,000rpm), optical drive, GTX 285 and 8800GT installed, with no problems other than the creativity necessary to cleanly wire everything up in the first place.

[Cindori]

I'm not sure I entirely believe that the power supply can't handle it. I have the one of the most power hungry Mac Pro Apple has shipped (2007 8x3.0) with all the RAM slots full, 5 SATA HDDs (one of which is 10,000rpm), optical drive, GTX 285 and 8800GT installed, with no problems other than the creativity necessary to cleanly wire everything up in the first place.

He is talking abot ports, not watt.

Crossfire 4870 has already been done by users on this forum.

[grue]

He is talking abot ports, not watt.

Crossfire 4870 has already been done by users on this forum.

He/she/it clearly states, and I quote:

You could run splitters but then you're over the limit for the power supply so you are going to need a drive bay power supply to run those things.

[Abidubi]

Why are you buying a Mac?

Was that addressed to me? I already have the computer... since this one came out.

And as to why I would buy a Mac if I intend to play some games on Windows despite the possibility for top of the line hardware and lower costs:

A) I prefer OSX so so so much more than windows and use it exclusively for daily use. The OS is way better at multi tasking than windows is, which is a piece of crap from my experience.

B) I already own software for OSX and don't want to buy it all again for windows.

C) I would never touch a hackintosh, way too much trouble. Just flashing a graphics card is at the limit of what I want to do.

D) I only have room for 1 computer so if I have to choose between windows or mac, mac wins hands down.

E) I only use windows for a hand full of games that aren't available in OSX, totally not worth another computer to run that.

F) I don't need the most powerful graphics card in OSX as the most demanding games never get ported to OSX with the exception of doom 3 and quake 4. The games that need crossfire, SLI or the latest and greatest tend to stay on windows.

[Abidubi]

As an update, unless the mac card can be flashed to work with crossfire I think I'll be buying 2 XFX 1GB 4870s and flashing 1 of them (unless I really need to flash both, only need 1 display in OSX).

It's funny that the total cost in CAD including taxes and shipping is still about $50 cheaper than the apple 4870 before taxes.

I need to figure out the cabling though. My plan is 1 apple funky connector from each card to the MB, then using 1 standard connector that comes with the card for each card. To connect them I would need to get a SATA to 2X molex, then get 2 molex y splitters I think. Would this work?

http://c1.neweggimages.com/NeweggImage/ProductImageCompressAll200/12-226-018-04.jpg
Using 1 of these http://www.newegg.ca/Product/Product.aspx?Item=N82E16812226018

http://c1.neweggimages.com/NeweggImage/ProductImageCompressAll200/12-183-147-02.jpg
Then using 2 of these to make a total of 4 female connectors http://www.newegg.ca/Product/Product.aspx?Item=N82E16812183147

And then connecting 1 power cable from each card to it.
http://www.newegg.ca/Product/ShowImage.aspx?CurImage=14-150-394-S06&ISList=14-150-394-S01%2c14-150-394-S02%2c14-150-394-S03%2c14-150-394-S04%2c14-150-394-S05%2c14-150-394-S06&S7ImageFlag=1&Item=N82E16814150394&Depa=0&WaterMark=1&Description=XFX%20Radeon%20HD%204870%20HD-487A-ZHFC%20Video%20Card%20-%20Retail

I can't tell due to the resolution of the picture, but are the card's connectors male or female molex? They need to be male with this setup.

Also, how am I going to get the cables to the card? With the side cover on there is no room for wires.

[TheStrudel]

I'm not sure I entirely believe that the power supply can't handle it. I have the one of the most power hungry Mac Pro Apple has shipped (2007 8x3.0) with all the RAM slots full, 5 SATA HDDs (one of which is 10,000rpm), optical drive, GTX 285 and 8800GT installed, with no problems other than the creativity necessary to cleanly wire everything up in the first place.

How are you wiring it, anyway? Using molex from ODD, or splitting the PCIe power junction? There's been much debate but no definitive answer as to which is safer.

[brock2621]

Mac Pro's specification are very clear and i quote, "300W combined maximum for all PCI Express slots".

Whether or not they are fibbing... that's another issue...

[grue]

How are you wiring it, anyway? Using molex from ODD, or splitting the PCIe power junction? There's been much debate but no definitive answer as to which is safer.


The top molex I leave unadulterated.

Bottom molex is split into two molexes, one of which has a molex to SATA converter on it to power the HDD there, the other of which has a molex to PCIe converter on it. Then the cables all run through a small gap in the shelf and under the front fan.

[grue]

Mac Pro's specification are very clear and i quote, "300W combined maximum for all PCI Express slots".

Whether or not they are fibbing... that's another issue...

I believe that refers to the maximum supplied through the motherboard.

FWIW, the specifications also say that you can only have 8GB of RAM in the quad core Nehalem, but we know that's not true as well :)

[brock2621]

I believe that refers to the maximum supplied through the motherboard.

FWIW, the specifications also say that you can only have 8GB of RAM in the quad core Nehalem, but we know that's not true as well :)

LOL touche sir... ;)

[Abidubi]

Alright, well I went ahead and ordered 2 XFX cards. I'll flash 1 with the new ROM, see if it works, try using with a second card in crossfire without flashing that one, if they work then I'll keep them.

Now for the power, I'm hoping that single SATA will provide enough power for each card (I'm splitting the power half and half). The next thing is figuring out how to get the cables down from up there, since the door closes flush and doesn't leave any space. There is however a small 1cm hole at the front of the machine. I think I'll have to yank off the end of the molex connectors and splice the cables together after passing them through the hole.

If that doesn't work, what about getting a PCI card for internal SATA ports and using an adapter on that to power the graphics cards??? Anyone ever try that before?

[Abidubi]

Well the cards arrived. Right now I have the apple 4870 in with the XFX card linked with crossfire. I booted up in windows (no flashing) and it ran just fine, no crossfire though and no change in benchmarks. Ran in OSX and everything is normal. System profiler shows the second 4870 with the same ROM and EFI (even though it is still the PC ROM). The XFX is also behaving well with the fan humming along quietly, not running at full speed. That was the goal of my test so far, to see if A) the cards computer would boot with 2 cards B) there would be sufficient power to both cards C) that an unflashed 4870 linked with crossfire would behave well under OSX (so I only need to flash 1 of the 2 cards).

I have each card powered half and half with the mother board and the ODD SATA connector. Seems fine to me.

I am now going to remove the apple card and flash one of the XFX cards. Wish me luck.

[Abidubi]

Ok, well I finally managed to flash the XFX card and it worked fine in both windows and OSX. One thing though is a very annoying buzzing when it is working hard. The higher the FPS the higher pitch the buzz. It is quite loud and was not at all present with the apple 4870. I swapped one XFX for the other non-flashed one and it also exhibits the same behavior, so it isn't a defective card.

Can anyone with a PC 4870 comment on that? I seem to remember my X800 doing that in my old G5, but I didn't think modern cards still do that.

[GrnEydDvl]

Did you get a chance to test the two PC cards installed at the same time under OS X and crossfire'd in Windows?

[Abidubi]

Yes and everything works fine, no power issues. I flashed 1 of the 2 cards and running OSX everything is just fine (of course no crossfire available). In windows crossfire works and makes a big difference in some games. However it is clear to me why apple does not support crossfire in OSX yet. It simply isn't ready. There are lots of minor graphical glitches from flickering clouds to faint dark rectangles stretching across the screen. Some games work great with it though with no glitches. However, you can disable crossfire on the fly, so if it causes problems you just disable it.

Biggest problem for me though is the very loud buzzing I am getting. I think the cards may be somewhat defective or just a bad batch. It is nothing that would damage the cards or computer, but it is very very annoying. I might RMA these cards and try another pair, maybe try a different brand, but if that doesn't work I'm just going to get a 285. Like I said, when it works it works great, but the buzz I am experiencing is too much.

And the buzz is present no matter what. I have tried connecting the display to different ports, using 1 card with just the apple 6-pin connectors, trying both cards separately, underclocking them, overclocking them, flashed or unflashed.

It's worth noting though that I haven't seen anyone else on this forum who flashed an XFX card report the buzzing sound.

[matthew.russo]

just thought I would drop my notes here, originally when I had the Apple ATI oem 4870's crossfire was a no go. Just recently I put Win7 x64 with the latest drivers from ATI (9.11 package) and it has allowed me to enable crossfire. So no issue with the Apple OEM 4870 cards from what I can report. I haven't been able to find anyone else who can test it but in my case I can confirm it is 100% working in crossfire.

[VirtualRain]

just thought I would drop my notes here, originally when I had the Apple ATI oem 4870's crossfire was a no go. Just recently I put Win7 x64 with the latest drivers from ATI (9.11 package) and it has allowed me to enable crossfire. So no issue with the Apple OEM 4870 cards from what I can report. I haven't been able to find anyone else who can test it but in my case I can confirm it is 100% working in crossfire.

That's a very interesting find!!! Everyone here had assumed Apple or ATI had intentionally borked CF in firmware... now we know it was just a driver or OS issue. Good stuff! :)

[ildondeigiocchi]

just thought I would drop my notes here, originally when I had the Apple ATI oem 4870's crossfire was a no go. Just recently I put Win7 x64 with the latest drivers from ATI (9.11 package) and it has allowed me to enable crossfire. So no issue with the Apple OEM 4870 cards from what I can report. I haven't been able to find anyone else who can test it but in my case I can confirm it is 100% working in crossfire.

That's very interesting to hear since I have a second Apple 4870 and wanted to install it in my Mac Pro for gaming purposes in windows however, the fact that crossfire was disabled made me cancel this idea. However, this has sparked new hope. Just one question, by installing a second Apple 4870 and an addition ODD power supply would I be voiding the Applecare warranty?

[matthew.russo]

That's very interesting to hear since I have a second Apple 4870 and wanted to install it in my Mac Pro for gaming purposes in windows however, the fact that crossfire was disabled made me cancel this idea. However, this has sparked new hope. Just one question, by installing a second Apple 4870 and an addition ODD power supply would I be voiding the Applecare warranty?

Its been mentioned many a time that running the second card off the sata and/or pata connections are ok. But to the point, i think modifying it in any away apart from what is intended would void your warranty. But what is to stop you removing what you added when you have to bring it in to get repaired if need be....

[ildondeigiocchi]

Its been mentioned many a time that running the second card off the sata and/or pata connections are ok. But to the point, i think modifying it in any away apart from what is intended would void your warranty. But what is to stop you removing what you added when you have to bring it in to get repaired if need be....

That's true... however, before i continue with this idea i want to see that other users have been able to enable crossfire under windows 7 which I will be upgrading to.

[ildondeigiocchi]

Both 4870's you have running in Crossfire are Apple OEM versions or is one of them a PC (XFX) version because both of mine are Apple 4870's.

[matthew.russo]

Both 4870's you have running in Crossfire are Apple OEM versions or is one of them a PC (XFX) version because both of mine are Apple 4870's.

Both are Apple OEM 4870's.

Here is my whole setup http://www.flickr.com/photos/36197914@N08/sets/72157616169842077/

[matthew.russo]

That's true... however, before i continue with this idea i want to see that other users have been able to enable crossfire under windows 7 which I will be upgrading to.

Couldn't agree more, I haven't seen anyone else test it yet.

[ildondeigiocchi]

Nice setup... I have a question though... I saw that you used a ODD power supply. Does it constantly stay on or only once the computer starts?

[matthew.russo]

Nice setup... I have a question though... I saw that you used a ODD power supply. Does it constantly stay on or only once the computer starts?

I had a hell of a hard time finding one to suite. The answer is that it turns on when the PC turns on. It is initialised by a PATA power connector. Simple, smart and it works.

If you looking at fitting it into an 06 or 09 mac pro check first if it can fit, mainly the cables. I had a hard enough time on the 08 mac pro but got it. The 08 model has a hole where the CD tray is to get the cables through. Any questions though regarding my install let me know.

[chiefroastbeef]

Do you have any cooling issues with two cards running max on games?

[matthew.russo]

Do you have any cooling issues with two cards running max on games?

Nope, it runs cooler than my 8800GT and quiter. The desk it is in is rather closed in so no the best airflow in there either. I found when CF wasn't working it ran hotter than when CF is working. The cards work less.

[chiefroastbeef]

That is awesome! Yea I look at your last picture and saw how claustrophobic your mac pro is (computer rights violation), it must be a pain taking that out and servicing it! That is a very clean setup as well! Where did you get that stand holding up your right screen?

[matthew.russo]

That is awesome! Yea I look at your last picture and saw how claustrophobic your mac pro is (computer rights violation), it must be a pain taking that out and servicing it! That is a very clean setup as well! Where did you get that stand holding up your right screen?

haha yeh, the desk is a bit more cleaned up (got a wireless printer) got rid of other clutter under the desk really, been meaning to cut a bit of a bigger hole behind the mac pro but it vents enough hot air over the top of it. Not the worse thing to take out and work on.

It is a Kensington Smart Fit Monitor Stand http://www.kensington.com/

[chiefroastbeef]

Appreciate the link Russo, good luck on the mac pro vent project! Let that horse breathe!