Dual GPU Mac Pro 2008 - how to power?

[r6mile]

Do this, leave side panel off.

The 570 with fan at end will spin fan at boot, but it will stop at desktop, in slot 1 of a 3,1. The one with fan in center will not do this.

Thanks for your message. Are you suggesting that the 570HD (with the fan in the centre) needs to have the mac pro side panel off in order to work?

But anyway all of this is very annoying. I've decided to sell both GTX570s, and the GT120, and just bite the bullet and do what I should have done from the start and get a EVGA GTX680 and flash it on Windows. In hindsight, seems quite pointless to have had all these cards passing through the house (and giving eBay their 10% commission every time!). But trial and error... Can anyone confirm there are no incompatibility issues between the EVGA 2GB GTX680 (normal version, not superclocked, classified, or anything like that), and the 3,1 Mac Pro? Also, what sort of PSU connectors does this card need (is it two 6-pin connectors)?

Question - do I need to have full Windows installed in the computer, or is it possible to do the flash from a bootable flash drive with Windows (or some version of DOS) installed?

 

[nigelbb]

For maximum guaranteed compatibility get an EVGA 2GB GTX680. AFAIK all of these can be flashed. The thread on compatible cards has other brands confirmed flashable with part numbers. https://forums.macrumors.com/threads/confirmed-and-possible-flashable-gtx-680-models.1578255/
Unfortunately it's becoming difficult to find a used EVGA PC GTX680 as everyone is trying to cash in on the premium price they can command when flashed for the Mac Pro.

This EVGA card at £150 will be fine http://www.ebay.co.uk/itm/eVGA-GeFo...651451?hash=item2a61653e3b:g:q7MAAOSwQYZWvwPb
This Zotac at £120 looks like the reference design so should be OK too http://www.ebay.co.uk/itm/Zotac-GTX-680-/262271384125?hash=item3d1097ba3d:g:c~kAAOSwxN5WYHmf
The easiest way of installing Windows is onto a separate disk using BootCamp. Make sure that the GTX680 is the only card in the machine as Windows freaks out if there are two different graphics cards installed.

It looks like it is possible to boot from a CD-ROM with DOS & all the files required for flashing & this may be easier than installing Windows https://forums.macrumors.com/threads/yes-you-can-boot-ms-dos-on-macpro-dvd-fw-flashing.238190/

 

[r6mile]

For maximum guaranteed compatibility get an EVGA 2GB GTX680

Thanks a lot, that's exactly what I bought yesterday. Saw it auctioned on eBay and made the seller an offer for £110 which he accepted, and he was local so I collected yesterday and no shipping fee.

I am going to flash it next week and will let you know how it goes.

P.S: On a separate point, I now have two GTX570s (and an Apple GT120) if anybody is interested...

 

[r6mile]

Update:

I was able to successfully flash the GTX680, but this was not without hiccups.

1. The Windows installer came up with a weird error, that after some internet digging told me that the Windows 7 installer sometimes gets confused with multiple hard drives, so I had to remove the PCIe SSD drive with OS X from the computer for the installation process.

2. Despite all the guides on this forum and on the internet, few of them actually attach the ROM file, which really does take quite a bit of digging to find the GTX680 2GB Rom. In the end, I used this guide which included the file.

3. Then, I downloaded nvflash from here, but it just didn't actually start the flashing process despite trying several times. Turns out, that version 5.236 of nvflash is some weird OEM version that just didn't actually flash. So I had to download an older version, I used this.

After all that, the GTX680 was finally successfully flashed and so far works without hiccups!