xfx 750a-SLI: PCI-e issue

kamor4

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Nov 27, 2008
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Hi people. I've just received a new XFX 750a-SLI motherboard and a second video card. So when i finnished installing everything, I plugged in the DVI adapter to the top video card. But then the screen goes black while everything boots up to windows... I tried switching both video cards, nothing. And everything is fine when i boot up with the DVI cable in the second video card. But the first PCI-e slot doesn't seem to read the video card. So there is no problem with the cards. I also get some short beeps just before booting into windows. When i open the computer case while its running, the DIMM sockets are showing red lights. Tried re-replacing my RAM aswell, but its still the same. So is the problem in the motherboard or could it be something else? Any help would be much appreciated.

This is what i have:

XFX 750a-SLI
AMD Phenom 9550
CORSAIR 4GB DDR2 800mhz
2x NVIDIA GeForce 9800 GTX+ OC


//Thanks
 

deanos

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Dec 15, 2008
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I have a very similar problem...

XFX 750a Mobo, with AMD 6000+ 4 GB RAM and 2 XFX 8800GTX Alpha Dog GPU's.

I cannot get it to boot, even with 1 GPU installed!

What I have discovered, is the issue with power!

The mobo has an 8 pin 12V power connector, but my PSU only has the standard 4 pin connector!

Apparently, this is where the problem lies! In order to use additional GPU's, you need to have all 8 pin's connected?!?!?!

Is there anybody there who could perhaps confirm this for us????

Many Thanks

Dean
 

hellix2

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Dec 16, 2008
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My understanding is that this motherboard does not properly support the Phenom Quad cores due to the lack of wattage. I believe the board supplies 90W while the Phenoms require somewhere around 120... I may have the numbers mixed up, but that is what I was told when I purchased that board. Also the default PCIe slot on the board is the one farthest from the CPU. I'm not sure as to why they felt it necessary to do things backwards with the PCIe slots, but they did. Another thing is the SLI jumpers on the board itself. Again, I'm not sure why they decided to put manual jumpers on there, but i don't own the company. /shrug. The only way I could get SLI to work was to move all four jumpers one step towards the CPU. You also have to get into BIOS and enable SLI. Keep in mind that this board has dual BIOS, one for OC and one for normal. Thus far I've had no success with the OC BIOS, as i can't get it to boot properly, or recognize SLI. I'm guessing that my issue is user based =) They also decided to field this mobo with no real documentation or instructions.
However many bad things this board brings with it, once it is operational it is awesome. Stays cool, is fast, and has a lot of options (if you can figure them out).
 

deanos

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Dec 15, 2008
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Well, I finally purchased a new PSU!!!!!

1000W!!! Woohooo!

Both cards are now installed and are running in SLI!

Only 1 problem now!
I get random freezing and sometimes I get a blue screen of MS death stating that my Graphics Card has gone into an infinite loop or something like that!!!!

This is VERY irritating!

Any idea's???????
 

tkgclimb

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May 9, 2009
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kamor4, and deanos
I have that board, and I found the same problem, but here is what i figured out, (and i don't know if you guys already knew this and won't fix your problem), but anyway the green pci-e (secound slot) is the x16 slot the top one is the 8x pci-e slot, in sli it runs at 8x speeds because of this. But anyway since it is like that the second not the first is the primary GPU slot which means with one GPU, it needs to be in the green slot and with two running in sli, i assume that the monitor has to be plugged into the second slot as well. And don't forget the sli jumpers and BIOS settings.
 

tkgclimb

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Thats wierd because I have a more stable boot and OC if I only boot in the OC bios, but i can't figure out the difference between the dual bios and the OC
 

deanos

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Dec 15, 2008
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Well, I eventually ended up returning the board!

I got too frustrated with it!!!!

I am now using my old ASUS M2N SLi Deluxe board.

It's been zapped by lightning 2, none of the onboard network cards work anymore, but it is still running and running great!!!

Oh well... :)