Precise instructions for getting x2 ATI Radeon HD 5870's in your Mac Pro (2009-2010)

Discussion in 'Mac Pro' started by blackwoodfx, Jan 9, 2011.

  1. KingRichard1st macrumors newbie

    Sep 12, 2011
    Ok I have a Mac Pro 2008 and want to do this...

    Hi Revel,
    I really want to do this as I have an XFX 6870 Radeon Black Edition (dual fan) which works great and I'd love to pick up a second on for Crossfire! The PSu you stated is no longer available so I'm looking at this:

    You stated that some of your instructions would not apply to the 2008 (3.1) Mac Pro! Could I ask which numbers in the list would not apply?
    Many thanks for your very detailed post btw. :)
  2. shissler1987 macrumors newbie

    Oct 13, 2011

    I tried this, just with the power of the dvd drives instead of the HDDs. And it seems to work. Extra PSU should not be nescesary.
  3. fotomiami macrumors newbie

    Dec 27, 2006
    Two questions:

    1- Do you need to buy one or two crossfire bridges?

    2- Why do you have to alternate between right and left ports on different cards?
  4. shissler1987 macrumors newbie

    Oct 13, 2011
    you don't. Some people have run some benchmarks with non, one and two cf bridges. They found out that you ll get a few more Fps while playing with two bridges. Thats all


    can anyone confirm to have blown up his mac pro by not having the extra psu?
  5. MacVidCards Suspended

    Nov 17, 2008
    Hollywood, CA
    Here's your chance to be the trailblazer !!!
  6. Toumak macrumors member


    Jul 26, 2010
    Hi !

    Just 2 questions for you fellas :D

    How is the FSP X5 noise ? Is it quiet or noisy ?

    Do some of you used the VisionTek PSU instead ? What about its noise too ?

    I plan on getting a second 570 to SLI Battlefield 3 :eek:
    Thanks in advance !
  7. BigJohno macrumors 65816

    Jan 1, 2007
    San Francisco
    I have read you don't need an eps. There are a couple video that don't have one and they say everything runs ok. You just need the splitter.
  8. Toumak macrumors member


    Jul 26, 2010
    Already tried this, and it was not the best : I guarantee you are affraid of burning your PSU while doing this ...

    And imagine : 2 570, when there shouldnt be enough power for 1 (the DirectCU uses 2*6pins + 1*8pins).
  9. BigJohno macrumors 65816

    Jan 1, 2007
    San Francisco
    But doesn't the mac pro have a 980 watt power supply. And if you have a single processor you should have enough for 2 5870's. Not sure about nvidia cards.
  10. nweash, Nov 1, 2011
    Last edited: Nov 1, 2011

    nweash macrumors newbie

    Dec 28, 2008
    in the process of installing this now..waiting for second 5870.

    so far i can tell you his psu is no longer available and the only other one on new egg is the fsb. if you choose that psu then the 4pin molex to sata adapter is too long to fit in chassis.

  11. Toumak macrumors member


    Jul 26, 2010
    Yes, the PSU has enough power to handle 2 cards, but the PCI-E lanes can't handle too much power : you risk to burn them => motherboard dead ...
  12. strausd macrumors 68030

    Jul 11, 2008
    Hi, I have a 5870 in my MP and I want to add a 5770. I have an optical drive and an SSD filling both optical drive slots.

    Because I only want to add a 5770 and not a 5870, would I need another power supply? If so, how would I set that up if I cannot put the power supply inside the case?

    If I do not need an extra power supply, what cables will I need to power the 5770?
  13. nanofrog macrumors G4

    May 6, 2008
    I would recommend using a 2nd PSU to power up the 5770 (and newer when/if you decide on another upgrade) so you don't draw too much current over the PCB traces that supply the GPU power connectors on the logic board (or too much current from the +12V rails those connectors are attached to).

    BTW, I do recall at least one MR member that did this (used splitter cables), and it melted the HAL and shorted (Hot Air Leveling solder on the PCB traces). End result = new logic board.

    As per what you can do, there's two possibilities to run a 2nd PSU for the graphics card:
    1. Remove the SSD and place it elsewhere in the system or externally (not that difficult to relocate internally with a little creativity - think Zip Ties or Velcro to mount it for example). Internal would be the best way to go, as I assume the SSD is your boot disk. Then use a 5.25" Graphics Card PSU (example) in the 5.25" bay the SSD currently occupies. This is nice and clean too BTW vs. the other alternative.
    2. Use a standard computer PSU externally, and jump the green and black wires together to power it up. Run the 6 pin PSIG cables through the bottom of the side panel or through an open PCI bracket. Not pretty, but it works. May be a bit cheaper too.

    No special cables needed with either solution (just use one of the 6+2 pin connectors as a 6 pin connector on the 5770).

    Hope this helps, and good luck. :)
  14. strausd macrumors 68030

    Jul 11, 2008
    Would I be able to have the 5.25" power supply sitting on top of the MP and have the cables go into the MP via an empty PCIe slot? Would this require some extension 6 pin power cables?
  15. wa5655 macrumors member

    Jun 12, 2010
  16. nanofrog macrumors G4

    May 6, 2008
    Yes you could do that, but at that point, it's not any different than using a standard PSU (still visible externally, though the 5.25" is smaller and might look a bit better). Depending on the deals you can find, you may be able to find a standard PSU you'd be able to live with for less money.

    If you decide to run the 5.25" externally, you'll need a Molex extension cable (pass it and any other cables through an open PCI bracket that doesn't have a card installed), as that's what is used to turn the unit on (rather than jump the green and black wires in the main board connector on a standard computer PSU). 6 pin PSIG extensions may also be needed, as I'm not sure how long the factory cables are.

    They use a 4 pin Molex connector to turn it on (fires it up with the rest of the system when the Power switch is pressed).

    Take a look at this unit, and examine the photos (particularly the rear; there's 3 connectors - one is the AC power, the output GPU cable assembly, and the 4 pin Molex that turns it on).

    BTW, I didn't link this one before, due to:
    1. More expensive.
    2. X on the front lights up (figured most might find that annoying, and though it's supposed to allow users to change the color, I don't see any switches for this, let alone one to turn it off = I took the cautious approach).
  17. strausd, Nov 17, 2011
    Last edited: Nov 18, 2011

    strausd macrumors 68030

    Jul 11, 2008
    Well that is good to know. I will be looking to see which would be cheaper.

    Would there be any downside to have a PSU on top of the MP?

    What would the extended molex cable plug into?

    Would I need to do this sort of thing for a standard PSU or only for the 5.25" PSU?

    As a PCIe 6 pin extender, would this extension cable work?

    If I do not need an extended molex cable for the normal PSU and I can find a good deal on one, that may be the easier route.

    Could there be any potential over heating problems with an external PSU laying on top of the MP or flat on carpet?

    And what wattage would you suggest for either a 5.25" or normal PSU?

    And for an external normal PSU, how would this one do? It is partially modular so I wouldn't have so many cables laying out and its only $40. And to turn it on, would I need any special cables or just flip the switch on the back?
  18. MacVidCards Suspended

    Nov 17, 2008
    Hollywood, CA

    Sometimes we get so caught up in thinking one way, that we aren't thinking at all.

    1. A simple molex to sata power adapter allows this unit to be used in newer Mac Pros. $5, problem solved.

    2. The light up "X" that has you so upset IS the switch. Push it and color changes. Push it again, the color changes again. Cycle through the colors and there is even a choice that results in no light at all. You were wearing the Ruby Slippers the whole time, just had to click your heels.
  19. nanofrog macrumors G4

    May 6, 2008
    From a performance issue, No. You'll need to take a can of compressed air to it from time to time in order to blow out the fan and heat sinks, but that's it (will get dirty over time, particularly sitting out in the open like that). On the plus side however, it will run cool so long as the vents and/or fans aren't covered up.

    Appearance wise however, you may not like it (additional unused cables to deal with unless it's a fully modular unit).

    It depends on the machine (actual connector providing the power in the MP, as some models have Molex <2006 - 2008>, and others SATA <2009 on>).
    • If the optical bay's use a Molex connector, then you just need a Molex Extension cable.
    • If it's a SATA backplane (single wide cable that carries both power + data), then it could be a bit more involved, particularly if that's the data connection for the SSD. But it's possible (backplane extension cable between the MP and SSD, and tie into the power cables with a Molex extension via wire nuts, crimp connectors, or solder + heatshrink tubing - just match up the colors and locations).
    • If you're not using the SATA connection in the empty optical bay (just need power), and it's a 2009 or newer, all you need is a SATA to Molex adapter + Molex extension cable connected together.
    In terms of getting power to a Molex connector as a means of powering up the PSU, this is only for the 5.25" graphics card units.

    A standard PSU would require you to connect the green and black wires in the main board connector together (turns the rest of the PSU's rails ON).

    Yes, this is what you'd need to extend the 6 pin PSIG connector it it's too short.

    As long as you don't cover up the vents, No (needs those unobstructed for good airflow).

    450W should be plenty, particularly as there won't be any other devices attached (additional loads). It should also make it easier to find a decent unit that you won't have to pay an arm + leg.

    BTW, most of the ratings advertised are peak values, not continuous values, unless specifically stated otherwise (divide by the square root of 2 for a continuous value).

    Should be fine. Not the cleanest semi-modular I've seen, but the price is certainly attractive if you've no problem with it having an LED fan and whatever cabling mess will exist. ;)

    It depends on the MP used (kept it general until now, as it's just a slight variation on the cables, such as using a SATA to Molex adapter + Molex extension if necessary).

    Upset had nothing to do with it (more information involved to determine the recommended unit, but decided on a KISS approach).

    Assuming the X emblem does serve as the switch (which I do actually expect to be the case), then it's possible to use something like a paper clip through one of the holes, but it's not convenient to access (paper clip though a hole in the case isn't desirable IMO). But I didn't feel like downloading a manual or reading every single Feedback post there was to verify the emblem is the switch.

    My recommendation also took into consideration (it was only linked for the pictures, particularly of the rear, to show how it connected to everything). Combine this with the fact that cost is usually the primary deciding factor, the other unit offered the best balance IMO.

    BTW, saw a post on newegg's feedback section (quick glance) that indicates it resets it's color setting when powered off (where the determination of using a paper clip, toothpick, ... seemed inconvenient to me, as it would apparently need to be accessed frequently).
  20. strausd macrumors 68030

    Jul 11, 2008
    It is a 2010 MP and yes, the second optical drive slot is used for the SSD.

    In order to turn on a 5.25" PSU, could I use that extension cable you mentioned, plus a SATA splitter (to split for SSD and PSU), plus a SATA extension cable (data from extension cable to SSD), and a SATA to molex cable? Would all of that work or be too many conversions and extensions?

    How would that specifically be done? Would the PSU turn on every time I turn the computer on? If not, would it be bad to just keep the PSU on at all times?
  21. nanofrog, Nov 19, 2011
    Last edited: Nov 19, 2011

    nanofrog macrumors G4

    May 6, 2008
    No, it's not too many extension cables connected. :)

    All you need for cables are the following (5.25" run externally):
    1. Backplane Extension Cable (completely takes care of the SSD, as it has both data + power)
    2. Molex Extension Cable (you'll need to measure the distance to make sure you don't order one too short; they sell them in 12, 18, 24, and 36" lengths)
    What to do:
    1. Cut the correct Molex end off (or remove the pins from the plastic connector body, and snip off the crimped ends - gives you a couple of extra millimeters of wire if you need it).
    2. Splice the wires with the same color wire on the Backplane Extension Cable's power wires (you can use wire nuts, crimp connectors, or solder + heatshrink tubing).
    It's a quick and easy project (soldering would take the longest, but it's the most compact and cleanest way to go IMO). ;)

    Once you get the two cables assembled together, you just made a custom wire harness that provides:
    1. Ability turn the 5.25" PSU on when you startup the MP (via the Molex connector)
    2. Provide both data and power signals to the SSD (via the Backplane connector).
    And the best part is, it won't void the warranty (presume you have Extended Apple Care). :D

    All in all, this is the better way to go IMO, as it will be much neater than a standard computer PSU (smaller helps, but mainly due to less wire hanging out side the system).

    But I have to ask...:
    It's easy to relocate the SSD internally (i.e. Velcro or Zip Ties work brilliantly for this), so why not just install the 5.25" PSU in the 2nd ODD bay?

    The cable harness is the same as above (Molex wires won't need to be as long is all that differs).

    Jumping the green and black wires is what triggers the PSU.

    • If you put those 2 wires on a switch (example), you can turn the PSU off when the system is shutdown (general case).
    • If you leave them connected (i.e. wire, or removed from the Main Board connector and tied permanently with a wire nut or crimp connector), the PSU will stay on. The only way to turn it OFF is either with a switch on the unit (unit you linked has one), or unplug it if there's no actual switch (could run into this with a different unit).
    Since the unit you're looking at has a switch, I'd just tie them together and use the switch to turn the unit On/Off.

    Just remember to turn the external PSU On first (and turn Off last), then start the system to make sure the card has power when it begins the boot process (could stop the boot process and shut down the MP if the PSIG connector doesn't have power).
  22. strausd macrumors 68030

    Jul 11, 2008
    OK it definitely seems like this would be the way to go.

    So far I understand the SATA extension cable that would provide both power and data to the SSD.

    I am just a little confused on what to do with the molex cable, so let me try and see if I am understand this right.

    One end will go into the 5.25" PSU. On the other end, break off the plastic part so that it is just the wires. Cut off some of the rubber to see some of the metal wires.

    On the SATA extension, cut off some of the rubber to reveal some of the wiring. Then connect each color from the molex to the extension individually. Does that sound right?

    And just out of curiosity, would there be a way to do this without having to cut or break any cables/wires? For example, by using SATA splitters, molex to SATA conversions, and a SATA cable for data to the SSD? If so, what are all the wires I would need?
  23. Tutor macrumors 65816


    Jun 25, 2009
    Home of the Birmingham Civil Rights Institute
    Agreed. For over 2 years, I've been using FSP Group Booster X5s (with - the FSP Booster needs to know when your system is powered on and off) in my 2007 and 2009 Mac Pros for running dual O'ced H.I.S. 4890s. They work great.
  24. strausd macrumors 68030

    Jul 11, 2008
    So for dual processor Mac Pros, would the power supply be able to handle a 5870 and a GT120 without having to use a second power supply?

    If so, how slow would a GT120 be?

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