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General Category => Trash => Topic started by: SMIKX on June 17, 2015, 09:15:50 AM



Title: Mac Pro 2,1 PCI-Express speed ?
Post by: SMIKX 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



Title: Re: Mac Pro 2,1 PCI-Express speed ?
Post by: Fl0r!an 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).


Title: Re: Mac Pro 2,1 PCI-Express speed ?
Post by: SMIKX 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.