Register FAQ / Rules Forum Spy Search Today's Posts Mark Forums Read
Go Back   MacRumors Forums > Apple Hardware > Desktops > Mac Pro

Reply
 
Thread Tools Search this Thread Display Modes
Old Dec 14, 2012, 08:13 AM   #151
slughead
macrumors 68030
 
slughead's Avatar
 
Join Date: Apr 2004
Quote:
Originally Posted by darkcoupon View Post
Apple's a smart company, I doubt they would use plugs that were rated at 108w if the Logic Board tracers were only rated at 75.
Wait, am I understanding you correctly in that you're assuming the motherboard tracers HAVE TO have the exact same tolerances as the cabling???

If Apple is rating the circuit--from PSU to Mobo tracer to cable to GPU--at 75 watts, then the only thing we can be certain of is that every part of that circuit can tolerate at least 75 watts. It is utterly ridiculous to think Apple would (I'm guessing you're saying) pluck out individual copper fibers from the 6 pin plugs until they can only tolerate 75 watts just because the mobo can't do anymore., or not just leave them at their previous wattage.

Again: I don't care what the cabling can do, don't care what the PSU can do. I absolutely and totally reject the notion that they are all rated for the exact same wattage simply because that would be silly as hell. I don't know what the mobo tracers are rated for, but it's almost certainly not the same as the cabling (my guess is that it's less).

----------

Quote:
Originally Posted by darkcoupon View Post
So official Apple specs say 75W, but infact the connectors on the Mac Pro's LB are rated at 108. With cable rated at 110w, this guy is actually selling cables capable of delivering around 110w of power to the Graphics card and advocates their use for cards that require more than 225w. By those calculations at 108w per cable plug and 75w at the PCIe slot, that makes the total max output of the Mac Pro 291w.
He's making that assumption based on the plugs, not the tracers. That's what this whole thread is about.

Last edited by slughead; Dec 14, 2012 at 08:10 AM.
slughead is offline   0 Reply With Quote
Old Dec 14, 2012, 09:23 AM   #152
darkcoupon
macrumors regular
 
Join Date: Aug 2012
Quote:
Originally Posted by slughead View Post
Wait, am I understanding you correctly in that you're assuming the motherboard tracers HAVE TO have the exact same tolerances as the cabling???
Actually, you're understanding me incorrectly. What I'm saying is common sense dictates that the bottleneck of the system is more likely to be the mini 6-pin plugs on the LB than the LB traces themselves.

If the plugs are actually rated at 108w as stated in the link that I posted earlier, it's probably safe to assume that the LB traces are rated higher. An educated guess for trace tolerance would be somewhere in the ballpark of 110w-150w.

That's not to say if you damage the plugs the MB will be safe, but it's likely that the actual tolerances of the system are closer to 250w than was previously assumed.

Last edited by darkcoupon; Dec 14, 2012 at 10:48 AM.
darkcoupon is offline   0 Reply With Quote
Old Dec 14, 2012, 09:40 AM   #153
Lord Blackadder
macrumors G4
 
Lord Blackadder's Avatar
 
Join Date: May 2004
Location: Sod off
Quote:
Originally Posted by revelstudios View Post
Thanks for your completely unnecessary and inaccurate contribution here, MacVidCards.

<snip>

Just one more reason for me to not bother coming back here. Adios.
You might be right in the end, but the only certainty here is that nobody here actually knows precisely how much your cards are drawing and what the safe limits of the Mac Pro are in terms of power supply to your card. nobody has any firm evidence of how close you are to the safe operating limits of the Mac Pro's logic board. Your evidence is anecdotal, and others here are making educated guesses. Neither is the same as official specs or firsthand knowledge of the design.

How much power can those traces handle safety? Until we know that number it is prudent to be conservative. The less you know, the more conservative you must be in order to ensure that you have some sort of safety factor. That doesn't mean you can't push your own hardware as far as you dare. It's your hardware, and I'm glad you shared your experience.

Someone previously suggested testing a Mac Pro to destruction. That is obviously going to be an expensive test (and I'm not volunteering my Mac Pro! ) but it might provide some useful data...it would have to be a 5,1 to be relevant, of course, and even then it would probably only provide a ballpark figure. But it would be something.

...or perhaps it would make sense to try and get in touch with an engineer who actually has firsthand knowledge of the Mac Pro logic board's design and ask them about it. It sounds like a long shot, but you never know. There are people out there who know the answer to this question.
__________________
Oh, God, God, God! What on earth was I drinking last night? My head feels like there's a Frenchman living in it. - Edmund Blackadder
Lord Blackadder is offline   0 Reply With Quote
Old Dec 14, 2012, 11:16 AM   #154
lixuelai
macrumors 6502a
 
Join Date: Oct 2008
My friend just bought this card for his Mac Pro (used to be mine, I sold it to him ):

http://www.newegg.com/Product/Produc...82E16814121560

He wanted a HD7970 to play games in Windows at 2560x1600. That Asus card has 2x 8 pin but is stock clocked. Power draw and distribution will be near identical to the GTX570 which is considered a pretty safe choice.

If his computer blows up any time I will be sure to update this thread
lixuelai is offline   0 Reply With Quote
Old Dec 14, 2012, 01:17 PM   #155
666sheep
macrumors 68040
 
666sheep's Avatar
 
Join Date: Dec 2009
Location: Poland
Quote:
Originally Posted by lixuelai View Post
My friend just bought this card for his Mac Pro (used to be mine, I sold it to him ):

http://www.newegg.com/Product/Produc...82E16814121560

He wanted a HD7970 to play games in Windows at 2560x1600. That Asus card has 2x 8 pin but is stock clocked. Power draw and distribution will be near identical to the GTX570 which is considered a pretty safe choice.

If his computer blows up any time I will be sure to update this thread
Convince him to play a little with VGA hotwire and we'll soon have an update
666sheep is offline   0 Reply With Quote
Old Dec 16, 2012, 02:32 PM   #156
syntho
macrumors newbie
 
Join Date: Dec 2012
Hello. I do not understand one thing, nvidia 285 mac edition has a 204 watt consumption, however the 7970 250 Watt. I do not understand what the problem is. the limit is 300 watts. http://arstechnica.com/apple/2010/10...010-mac-pro/2/

Last edited by syntho; Dec 16, 2012 at 02:44 PM.
syntho is offline   0 Reply With Quote
Old Dec 16, 2012, 03:35 PM   #157
brentsg
macrumors 68020
 
brentsg's Avatar
 
Join Date: Oct 2008
Quote:
Originally Posted by syntho View Post
Hello. I do not understand one thing, nvidia 285 mac edition has a 204 watt consumption, however the 7970 250 Watt. I do not understand what the problem is. the limit is 300 watts. http://arstechnica.com/apple/2010/10...010-mac-pro/2/
I've never seen the 300W claim anywhere except in that review.
brentsg is offline   0 Reply With Quote
Old Dec 16, 2012, 03:44 PM   #158
Asgorath
macrumors 6502a
 
Join Date: Mar 2012
Quote:
Originally Posted by syntho View Post
Hello. I do not understand one thing, nvidia 285 mac edition has a 204 watt consumption, however the 7970 250 Watt. I do not understand what the problem is. the limit is 300 watts. http://arstechnica.com/apple/2010/10...010-mac-pro/2/
I believe this 300W value has already been raised earlier in this thread, i.e. it's the 300W to all 4 PCIe slots themselves (4 x 75W = 300W max). This value is independent of the power supplied by the auxiliary 6-pin connectors on the motherboard.
Asgorath is offline   0 Reply With Quote
Old Dec 16, 2012, 04:15 PM   #159
El Awesome
macrumors 6502
 
Join Date: Jul 2012
Location: Zurich
Quote:
Originally Posted by Asgorath View Post
I believe this 300W value has already been raised earlier in this thread, i.e. it's the 300W to all 4 PCIe slots themselves (4 x 75W = 300W max). This value is independent of the power supplied by the auxiliary 6-pin connectors on the motherboard.
I still don't get this calculation - how can one device use all the power from 4 slots - given you would install a second GPU like a GT120 that doesen't need auxilary power but all the 75w from the PCIe slot, what then?
__________________
Hackintosh 3.5Ghz i7 3770k, 32 GB RAM, eVGA GTX 680 2048 MB SuperClocked, Samsung 830 128GB SSD
MacBook Pro Late '08 2.8 Ghz C2D, 4GB RAM, Nvidia 9400M & 9600M GT
El Awesome is offline   0 Reply With Quote
Old Dec 16, 2012, 08:26 PM   #160
syntho
macrumors newbie
 
Join Date: Dec 2012
Non capisco...

The slot format used by both PCI Express 1.1 and PCI Express 2.0 is the x16 PCIe slot. However, PCI Express 2.0 slots are subjected to sustain up to a maximum of 150 watts, and PCI Express 1.1 slots can sustain only 75 watts, which is exactly half of the PCIe 2.0 slot’s capability. Apart from this, the PCIe 2.0 standard enables slot power limits to change, in order to allow for the higher powered slots that support the latest high performance cards.

fonte: http://www.differencebetween.net/tec...i-express-2-0/

The pci-e 1.1 stated 50 watts, maximum tolerable
75 watts. The pci-e 2.0 75 watt said, maximum tolerable 150 watts.

https://discussions.apple.com/thread...art=0&tstart=0

Last edited by syntho; Dec 16, 2012 at 09:14 PM.
syntho is offline   0 Reply With Quote
Old Dec 26, 2012, 12:58 PM   #161
KBS756
macrumors 6502
 
Join Date: Jan 2009
Hey just a question about what was posted here in terms of 7970 GHz compatibility. Does the Brand who manufactures the Card matter or are all 7970 GHz compatible with the Mac Pro running 10.8.3. Does 10.8.2 not work then?

Also do I have to install 10.8.3 to remove a limit on GPU memory to 2GB which I believe was stated on here earlier?

Thanks in advance for clarification.
__________________
27" + 24" LED ACD; 2 x 3.33GHz X5680 Mac Pro, 16 GB RAM, 512 GB Samsung 830 SSD ,EVGA Geforce Titan Super-clocked; Early 2013 2.8Ghz 15in Retina Macbook Pro 16GB Ram 756GB
KBS756 is offline   0 Reply With Quote
Old Jan 4, 2013, 12:07 PM   #162
thema2000
macrumors newbie
 
Join Date: Jan 2013
hi! i have a problem!

i have this hardware

MB : gigabyte z77-Dsh3
cpu: i5 3570k
vga: gigabyte dual x HD7970
hdd : ssd corsair force 120gb


when I boot from USB, my pc reboots without let me read the error with-v

where can I find the 10.8.3 and where and how to install?
thema2000 is offline   0 Reply With Quote
Old Jan 4, 2013, 01:44 PM   #163
GermanyChris
Banned
 
Join Date: Jul 2011
Location: Here
Quote:
Originally Posted by thema2000 View Post
hi! i have a problem!

i have this hardware

MB : gigabyte z77-Dsh3
cpu: i5 3570k
vga: gigabyte dual x HD7970
hdd : ssd corsair force 120gb


when I boot from USB, my pc reboots without let me read the error with-v

where can I find the 10.8.3 and where and how to install?
Time to go to tonymac
GermanyChris is offline   1 Reply With Quote
Old Jan 27, 2013, 03:27 PM   #164
Old-Macs
macrumors newbie
 
Join Date: Sep 2012
Sorry, this Mac Pro PCIe Power page has been a background project since forever.. but i spotted this post, here's a link to it.. not really "Proof Read" at this point, but you should at least be able to follow the logic behind the cable design.

old-macs.com/misc/MacProPCIePower.html

<a href="http://old-macs.com/misc/MacProPCIePower.html">Mac Pro PCIe Power & Cable Theory</a>

explains the basic ideas behind WHY i designed the cables to use 18AWG wire instead of the typical 20AWG..

the entire design and testing idea was a result of my spotting the MacVidCards GTX 480 cards with two versions of the rom. then finding those firmwares someplace so i could experiment with a GTX 480 card and both versions of the firmware.
Old-Macs is offline   0 Reply With Quote
Old Jan 27, 2013, 11:24 PM   #165
MacVidCards
macrumors 603
 
Join Date: Nov 2008
Location: Hollywood, CA
 
Hey there, Old Macs. I think we have corresponded before.

Anyhow, your post is informative, but your page does not mention what happens if you run a de-tuned (MP Edition) GTX480 of ours on the standard 20 gauge cables. I hope that you found it worked fine.

I only ask because we are about to introduce a detuned and electrically modified GTX580 series with both 1.5 GB and 3.0 GB cards. They are both for use in Mac Pros with standard power cables. I have had to suspend development until I can get a new Logicboard as I have managed to fry one in my 2009 4,1/5,1 during testing.

So, I can now verify that running a GTX580 3.0 GB at stock speeds with standard cables can cause that lovely combo of ozone and burning electronic smells to emanate from your machine. My slot 1 is now dead and I have contacted DVWarehouse to buy a new logic board. Turns out there are 2 versions of logic board so I have to remove this one to find which one to replace with.

Let's hope that 2013 Mac Pro simply comes with 2 @ 6 pins and 2 @ 8 pins available internally. Would be a dream to be able to use not one but TWO powerful GPUs in there. Until then, people should remember that there is no magical Power Fairy running in your Mac Pro. It is beholden to the same laws of physics and heat as any crappy $50 PC.
MacVidCards is offline   1 Reply With Quote
Old Jan 28, 2013, 09:08 PM   #166
Old-Macs
macrumors newbie
 
Join Date: Sep 2012
hi,

yes indeed the MacVidCards "Low Power" GTX 480 rom worked just fine with the regular 20AWG cables, the (occasional under-stress) hangs were only with 20AWG cables and the "Full Power" rom..

the fact that you had to De-Tune the card and decrease it's power demand is what led to the desire-for and design-of the thicker cables.. i used to be an electrical contractor, so the idea of the wires reaching/exceeding capacity (and the results of that) was an obvious place to try and make a change in the system..

sadly it took almost 8 months before i found an engineer who understood HOW the thicker wires could be used and was willing to make the cables..
Old-Macs is offline   0 Reply With Quote
Old Jan 29, 2013, 12:37 PM   #167
InuNacho
macrumors 65816
 
InuNacho's Avatar
 
Join Date: Apr 2008
Location: In that one place
Quote:
Originally Posted by MacVidCards View Post
FWIW, I got a 7950, it is nearly as fast as 7970 and works with 2 @ 6 pins. Argument over. I guess I just need to start my own new personal "I too can re-confirm that my own previous discovery was correct" thread.
Which 7950 did you get in your Pro, most of the ones I've seen all require a 6 and 8 pin. Are you using an 8-6 adaptor?
InuNacho is offline   0 Reply With Quote
Old Jan 29, 2013, 02:41 PM   #168
handheldgames
macrumors 6502a
 
handheldgames's Avatar
 
Join Date: Apr 2009
FWIW.. The Gigabyte 7950 has 2 6-pin power inputs, 3 fans, a higher base clocked core and is rated as the quietest 7950 on the market. Was a great 6870 replacement in a 2009 mac pro. It's on sale at NewEgg for $299 as well.
__________________
2009 MacPro i7-990x, XP941 SATA Express Boot, 32GB RAM, AMD 7950/GTX 680, Seiki 4k, Dual 30" Dell 3007wfp-hc, VelocityX2-Samsung840, FrescLogic USB3, Software Developer/Hardware Designer
handheldgames is offline   1 Reply With Quote
Old Jan 29, 2013, 11:05 PM   #169
InuNacho
macrumors 65816
 
InuNacho's Avatar
 
Join Date: Apr 2008
Location: In that one place
Quote:
Originally Posted by handheldgames View Post
FWIW.. The Gigabyte 7950 has 2 6-pin power inputs, 3 fans, a higher base clocked core and is rated as the quietest 7950 on the market. Was a great 6870 replacement in a 2009 mac pro. It's on sale at NewEgg for $299 as well.
Sounds great! Hopefully 10.8.3 comes out soon enough so I can ditch my 5870 and snag a 7950 just in time for Metro Last Light.
InuNacho is offline   0 Reply With Quote
Old Feb 1, 2013, 10:11 AM   #170
mrprice33
macrumors newbie
 
Join Date: Feb 2008
Quote:
Originally Posted by InuNacho View Post
Sounds great! Hopefully 10.8.3 comes out soon enough so I can ditch my 5870 and snag a 7950 just in time for Metro Last Light.
I have a 7970 and I have it hooked up using the 6 pin connector and the 8 pin from the molex connectors that used to be hooked up to my superdrive. I should be okay, right?
mrprice33 is offline   0 Reply With Quote
Old Feb 2, 2013, 07:37 PM   #171
InuNacho
macrumors 65816
 
InuNacho's Avatar
 
Join Date: Apr 2008
Location: In that one place
Quote:
Originally Posted by mrprice33 View Post
I have a 7970 and I have it hooked up using the 6 pin connector and the 8 pin from the molex connectors that used to be hooked up to my superdrive. I should be okay, right?
I was advised by many here not to use molex connections for graphics card and instead go with a secondary PSU.
InuNacho is offline   0 Reply With Quote
Old Feb 26, 2013, 08:38 PM   #172
tnhansel
macrumors newbie
 
Join Date: Feb 2013
Quote:
Originally Posted by revelstudios View Post
Confirmed working, AMD Radeon HD 7970 GHz Edition on OS X 10.8.3, Mid 2012 Mac Pro, no flashing required. Also confirmed working since 10.8.1 beta. Strongly believe this is here to stay. Beautiful hardware. Real-time playback of full-resolution 4K footage in FCPX. Also tested with Adobe apps and lots of GPU crunching. Stable. No issues at all.

Image

Image
Thank you for sharing this and may I know where I can find the driver for xfx 7970? or do I just plug it into the mac pro?
tnhansel is offline   0 Reply With Quote
Old Mar 15, 2013, 08:40 AM   #173
barbaresque
macrumors newbie
 
Join Date: Mar 2013
Hi everybody,

First i want to apologize for my rudimentary english skills.

I own a Mac Par 5.1 (2010) and i want installing a Radeon HD 7970 on it.

Unfortunately, i am not familiar with "tweaking" and i have i don't know anything about electric systems.

I read with many interventions and enjoyed the quality and the simplicity of all the of them and i want to thank you all for that.

I came to the conclusion that the most safe and elegant was to install and additional PSU on the 5.25" but unfortunately, i am as i said beginner, and this operation seems to be complicated for me.

I want to ask you how "concretely" (and please pedagogically) can install a 8 pin / 6 pin cable from my PS to the card : http://fr.msi.com/product/vga/R7970-2PMD3GD5.html.
Do i need to by cables ? Where to plug them ?

Best Regard
barbaresque is offline   0 Reply With Quote
Old Mar 15, 2013, 11:51 AM   #174
DanielCoffey
macrumors 65816
 
DanielCoffey's Avatar
 
Join Date: Nov 2010
Location: Edinburgh, UK
If you can find a 7970 with 2x 6-pin sockets, you can just use the standard Mac Pro power leads that you would have got from your 5770/5870 card. You would need two of them.

If it has 1x8-pin and 1x6-pin, then while you *could* still power it from the Mac Pro, you would be at risk of damaging your Mac Pro by drawing more power than the traces on the logic board can handle. Some folks with cards that draw similar peak power to the 5870 (225W Max) do this with no problem in the short term.

The advice is that any card with one or more 8-pin power sockets should be powered from an external power supply, usually fitted into the optical drive bay.

In short, if your card has one or more 8-pins, you really should use an external power supply. After all, what is your Mac Pro worth to you?
DanielCoffey is offline   0 Reply With Quote
Old Mar 15, 2013, 07:55 PM   #175
barbaresque
macrumors newbie
 
Join Date: Mar 2013
Tank you for the reply Daniel.m
I couldn't find a 7970 with two 6 pin connectors but I found many 7950 with this configuration.
If I buy a 7950, what kind of cable do I need to buy and how to plug them in the
Mac Pro's Power Supply ?

Best regards
barbaresque is offline   0 Reply With Quote

Reply
MacRumors Forums > Apple Hardware > Desktops > Mac Pro

Tags
7970, mac pro, radeon

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Similar Threads
thread Thread Starter Forum Replies Last Post
AMD Radeon HD 2400 PRO in Mac Pro 1,1? paulrbeers Mac Pro 1 May 21, 2014 06:03 PM
AMD Radeon HD 7970 Compatibility in an 8 core Mac Pro Running Mountain Lion lextrickett Mac Pro 22 Oct 31, 2013 12:23 PM
Crossfire / sli setup with 2 radeon 7970 cards to mac pro Jani81 Mac Pro 1 Sep 22, 2013 08:14 AM
Where to get mac bios flash to radeon 7970? Jani81 Mac Pro 5 Aug 4, 2013 12:15 PM
Running a Mac Pro without a PCIE Fan and a HD 7970? harkkam Mac Pro 6 Nov 10, 2012 10:58 AM

Forum Jump

All times are GMT -5. The time now is 05:04 AM.

Mac Rumors | Mac | iPhone | iPhone Game Reviews | iPhone Apps

Mobile Version | Fixed | Fluid | Fluid HD
Copyright 2002-2013, MacRumors.com, LLC