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Author Topic: Mac Pro 2,1 PCI-Express speed ?  (Read 2677 times)
SMIKX
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Posts: 41



« on: June 17, 2015, 09:15:50 AM »

Hi,

I've done a lot of searching but still cannot get a clear answer re Mac Pro 2,1 video card PCI link speed.

I have seen references to this in Netkas's forums but at the time didn't think it was so important ( foolish).

I currently have a flashed Vapor-X HD 5870 in my 2,1 MP.  ( EFI boot screens OK with DVI - VGA )

In Sys Info/PCI Cards it shows the link speed as 2.5 GT/s.

Is this a built in limit for the 2,1 Mac Pro ?

My questions :

1. Which Mac Pro model will yield the maximum PCI speed with my present 5870 ( is that speed 5 GT/s ?

2. Is anyone getting the full 5 GT/s & if so what is your setup.

Many thanks in advance.

EDIT : Just found the answer here : https://forums.creativecow.net/thread/364/1982

          I'll be getting a Mac Pro 4,1

« Last Edit: June 17, 2015, 09:20:14 AM by SMIKX » Logged

Mac Pro 4,1 upped to 5,1 Dual Quad Core 2.93ghz 17Gb 480Gb SSD TRIM enabled.
Vapor-X HD5870 DVI to HDMI EFI OK.
10.6.8  10.9.5 10.10.5 Win 7. 
AREA USB 3.0 PCI card in OS X 10.9.5.
Fl0r!an
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« Reply #1 on: June 17, 2015, 12:46:06 PM »

Your Mac Pro has PCIe 1, so 2.5 GT/s is maximum. This does not limit the computional power of your GPU however, just the bandwidth for transfering data.

Additionally, most flashed PC cards will only run with 2.5 GT/s even on MacPro3,1+ without further modifications (e.g. removing resistor on the PCB or additional mods in the EFI).
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SMIKX
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Posts: 41



« Reply #2 on: June 19, 2015, 01:59:37 AM »

Yes, I recall seeing "having to cut with a hobby knife . ." comments here with dread.

But going from a MP 2,1 to a 4,1 will give me 64 bit ( plus faster EFI'ed GPU's  in Yosemite ) and also a 4,1's firmware can be upped so seeing that I can get a 4,1 MP in very good condition here for about ¥75,000 with at least 8 Gb RAM I will definitely be better off.

In any case, thank you for reminding me that I definitely do not want to cut traces on a video card.
Logged

Mac Pro 4,1 upped to 5,1 Dual Quad Core 2.93ghz 17Gb 480Gb SSD TRIM enabled.
Vapor-X HD5870 DVI to HDMI EFI OK.
10.6.8  10.9.5 10.10.5 Win 7. 
AREA USB 3.0 PCI card in OS X 10.9.5.
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