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Augustots

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Mar 23, 2021
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I ordered a used gtx780 my will arrive in a few days, I was wondering about the power cable they told me that the 780 has 2 cables, one 6-pin and one 8-pin, is that true?
in this case now i use the 8 pin cable for gtx960 and it will also work on the gtx 780 but i will also have to put another 6pin cable the one i had removed when i bought the mac pro used and it had a 1gb video card connected with a 6-pin cable.
am i doing the right thing? thank you.
 

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Augustots

macrumors regular
Original poster
Mar 23, 2021
133
15
Trieste
hi I wanted to know, I have the mac pro 2008 with 32 gb of ram, so there are 2 trays for the ram, each of these has 4 banks of 4 gb then 2 trays with 4 banks of 4gb each make a total of 32 gb.
would it be possible to leave 1 tray with 4 banks of 4 gb and on one tray put 4 banks of 8 gb?
so that you have a total of 48gb of total ram?
or are there problems?
thank you.
 

Augustots

macrumors regular
Original poster
Mar 23, 2021
133
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I saw that even the gtx970 4gb is very powerful, indeed 10% less powerful than the 780ti but still has 4gb inceve of 3, now I have placed the order and it goes like this.

anyway, just to know the gtx 970 is compatible with my mac pro 2008?
 

AlexMaximus

macrumors 65816
Aug 15, 2006
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I ordered a used gtx780 my will arrive in a few days, I was wondering about the power cable they told me that the 780 has 2 cables, one 6-pin and one 8-pin, is that true?
in this case now i use the 8 pin cable for gtx960 and it will also work on the gtx 780 but i will also have to put another 6pin cable the one i had removed when i bought the mac pro used and it had a 1gb video card connected with a 6-pin cable.
am i doing the right thing? thank you.

Back than when I still had my golden El Capitan setup in 2018, it looked like this in the pic below. I have used an EVGA Powerlink to connect my 980Ti. The big advantage of the EVGA Powerlink is that it balances out the power requirements between both powercables that go through the 6 pin Mac Pro cables. This way you avoid any shut down in case the GPU needs more juice during that rare 100% Power Loads. I have looked through my Mac Pro Goody-Box and I still have it here together with a Y Splitter and two 6 pin cables. You can have it all for twenty bucks + shipping to Italy. Its small and shipping should not be too expensive from South Bavaria, I am just across the alps..

IMG_5889.jpg
 
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Augustots

macrumors regular
Original poster
Mar 23, 2021
133
15
Trieste
hi I wanted to know, I have the mac pro 2008 with 32 gb of ram, so there are 2 trays for the ram, each of these has 4 banks of 4 gb then 2 trays with 4 banks of 4gb each make a total of 32 gb.
would it be possible to leave 1 tray with 4 banks of 4 gb and on one tray put 4 banks of 8 gb?
so that you have a total of 48gb of total ram?
or are there problems?
thank you.
HELP MY please.
 

Augustots

macrumors regular
Original poster
Mar 23, 2021
133
15
Trieste
Then I got the used gtx nvidia gforce 780, I didn't get the gtx 780ti because I couldn't find suitable prices, so I got a gtx 780, I installed it on the mac pro 2008 with the 2 6-pin cables and 8-pin put the nvidia driver and it works wonders.
But there is a problem, on the online benckmarks they say that 780 3gb is 40% faster than the gtx 960 4gb I had before, but in reality I tried with fcpx to export a 9 minute movie in 4k same clips same format but first with gtx 960 4gb and popi with the gtx780 3gb.
I was disappointed here are the results:
FCPX rendering test on Mac Pro 3.1.

9 minute video in 3840x2160 25p. Apple pro res 422.

Gtx 960 4gb export time Minutes 5.58.

Gtx 780 3gb export time 6.48 minutes.

so the 780 took almost 1 minute longer ... but why?
shouldn't it be more powerful and faster than the gtx 960 4gb?
thank you.
 

Augustots

macrumors regular
Original poster
Mar 23, 2021
133
15
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TOTAL disappointment the gtx 780 3gb with fcpx and with files in 4k converted to pro res 422 in the timeline proceeds with jerks and distorted audio while with the gtx 960 4gb it proceeded perfectly without problem and to think that the 960 is 40% less powerful than the gtx 780 !!!
in my opinion the problem is the gb, 3gb are few for the 4k that's why the gtx 960 with 4gb works better, I threw away 150 euros for a gtx 780 USELESS, too bad.
i will have to get a gtx 980!
 

Dayo

macrumors 68020
Dec 21, 2018
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hi I wanted to know, I have the mac pro 2008 with 32 gb of ram, so there are 2 trays for the ram, each of these has 4 banks of 4 gb then 2 trays with 4 banks of 4gb each make a total of 32 gb.
would it be possible to leave 1 tray with 4 banks of 4 gb and on one tray put 4 banks of 8 gb?
so that you have a total of 48gb of total ram?
or are there problems?
thank you.
Early 2008 Mac Pro can have 64 GB but you need to add a setting to limit Mac OS to only using up to 62 GB. That is, Mac OS can use up to 62 GB on that machine. There is some issue with 64 GB though unless limited.
However, if you have Windows and/or Linux installed, they can use the 64 GB if installed.

See: Max RAM in MP3,1. 62, 56 or 64GB and Can I have more RAM? Yes, you can run 62GB without speed penalty! in https://forums.macrumors.com/posts/27653988

Apparently, 56 GB may be the best max.
 
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AlexMaximus

macrumors 65816
Aug 15, 2006
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Early 2008 Mac Pro can have 64 GB but you need to add a setting to limit Mac OS to only using up to 62 GB. That is, Mac OS can use up to 62 GB on that machine. There is some issue with 64 GB though unless limited.
However, if you have Windows and/or Linux installed, they can use the 64 GB if installed.

See: Max RAM in MP3,1. 62, 56 or 64GB and Can I have more RAM? Yes, you can run 62GB without speed penalty! in https://forums.macrumors.com/posts/27653988

Apparently, 56 GB may be the best max.
Hi Dayo

I have seen in your signature that you are running a RX580 in a MP 3.1. Augustots tries to find the right GPU for his MP3.1 to do some 4K video stuff. Can you jump in and help him? Unfortunately I am primed on the 5.1 only. I told him earlier that he should get something strong like a 980Ti, but instead he got a 780 (non Ti) and was disappointed. Obviously you managed to circumvent the metal problem on your rig, hence that rx580 mentioned on your sig. what do you recommend? Go with a strong Nvidia or use that trick of yours to squeeze an AMD metal capable gpu in there?
Does this make sense for his 4K editing stuff? Of course the 3.1 will be bottlenecked by a slow single core score. Does this make sense in 2021, considering he has no budget to switch to something newer?
 
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Dayo

macrumors 68020
Dec 21, 2018
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Augustots tries to find the right GPU for his MP3.1 to do some 4K video stuff. Can you jump in and help him?
I don't know much about video needs but the RX 580 works without issue on a cMP3,1 especially if on Mojave or newer. It doesn't need any special stuff to work and there is no problem with Metal but it does need something like OpenCore and/or RefindPlus to get a bootscreen if required (see the "MyBootMgr" link in my signature). However, it works just fine without these and there will be a blank screen until the login window is shown after which everything is as normal.

I ran it with DosDude patched Mojave without bootscreen until I implemented RefindPlus/OpenCore and apart from a short period without bootscreen while loading, it was just fine. I kept my old HD 5770 for any need for bootscreen.

With RP/OC, along with a bootscreen, you can get GPU Acceleration on Metal AMD which I presume would be useful for video stuff. MyBootMgr will also attempt to do the acceleration for Nvidia but not sure it actually works. I think only DRM Streaming works.

Don't know much about video as said, but the RX 580 works just fine in a cMP3,1. However, it may not be the best choice if on HiSierra or earlier as I believe the required drivers were only firmed up in Mojave. It works on El Capitan but is quite slow and glitches. I think the experience will be more or less the same up to HiSierra.

As Augustots seems to prefer HiSierra, he might as well stick with the GTX 1070 Ti he ordered. he can also use MyBootMgr (Perhaps best to wait till next week when a new version is due) to set RP/OC up which should help ensure he gets a bootscreen with that as well.
 
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Augustots

macrumors regular
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Mar 23, 2021
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Thanks for your advice but I didn't understand one thing, does the AMD RX580 4gb nitro run on high sierra in the mac pro 2008?
because I think I understand that it works with mojave and not with high sierra, where am I wrong?
 

Augustots

macrumors regular
Original poster
Mar 23, 2021
133
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I saw that the gtx 1070 has 2 8-pin power inputs, but do I have to connect only one 8-pin plug or both?
thank you.
 

Dayo

macrumors 68020
Dec 21, 2018
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I didn't understand one thing
Maybe bullet points will be clearer:
  • RX 580 works fine on cMP3,1.
  • There is no issue or difference between how it works on cMP3,1 with any other.
  • The GPU drivers were only finalised in Mojave.
  • It therefore works well on Mojave and newer
  • I have tested it on earlier Mac OS as old as El Capitan which do not have the finalised drivers
  • It works but the performance is poor
  • You can expect similar poor performance up to HiSierra
  • You might as well stick with the GTX 1070 Ti you ordered since you seem to prefer HiSierra
 
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tsialex

Contributor
Jun 13, 2016
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Maybe bullet points will be clearer:
  • RX 580 works fine on cMP3,1.
  • There is no issue or difference between how it works on cMP3,1 with any other.
  • The GPU drivers were only finalised in Mojave.
  • It therefore works well on Mojave and newer
  • I have tested it on earlier Mac OS as old as El Capitan which do not have the finalised drivers
  • It works but the performance is poor
  • You can expect similar poor performance up to HiSierra
  • You might as well stick with the GTX 1070 Ti you ordered since you seem to prefer HiSierra
El Capitan don't have Polaris/Ellesmere (RX 460/480/560/580) drivers, Apple included it for the first time with 10.12.6 betas. You can only run El Capitan via the native EFI drivers and it's completely unaccelerated and most time useless beyond diagnostics or getting something done that don't require acceleration to work.

High Sierra have decent Polaris/Ellesmere drivers but the real support is after 10.14.5, where VideoToolbox compression/decompression/conversion hardware acceleration can be enabled.
 
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Augustots

macrumors regular
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Mar 23, 2021
133
15
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they canceled my order on amazon for the gtx 1070 8gb it seems to be no longer available, and the third time that happens, well then on an online second-hand market I found a used gtx 980ti for 290 euros shipped, it purchased will arrive in the week, but I saw that it has 2 8-pin inputs while I have an 8-pin cable, is it possible to connect only an 8-pin cable or do you necessarily need all 2 8-pin cables?
thank you.
 

tsialex

Contributor
Jun 13, 2016
13,455
13,601
they canceled my order on amazon for the gtx 1070 8gb it seems to be no longer available, and the third time that happens, well then on an online second-hand market I found a used gtx 980ti for 290 euros shipped, it purchased will arrive in the week, but I saw that it has 2 8-pin inputs while I have an 8-pin cable, is it possible to connect only an 8-pin cable
No.
or do you necessarily need all 2 8-pin cables?
thank you.
Yes. This GPU requires Pixla’s mod or external PSU.
 
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AlexMaximus

macrumors 65816
Aug 15, 2006
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577
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they canceled my order on amazon for the gtx 1070 8gb it seems to be no longer available, and the third time that happens, well then on an online second-hand market I found a used gtx 980ti for 290 euros shipped, it purchased will arrive in the week, but I saw that it has 2 8-pin inputs while I have an 8-pin cable, is it possible to connect only an 8-pin cable or do you necessarily need all 2 8-pin cables?
thank you.
Leave me your address in Italy in my email box and I will send you my EVGA power link with cable. You can have it for the shipping expense, this way you don’t need pixlas modification.
 
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