Dual SLI Question

This is to do with my Brothers computer, since for some reason the only card that will work in his primary PCI slot is a GeForce 7900 I figured his best option is to run SLI.

I'm new to it and he has no idea anyway so I was wondering if someone could help with the following:

1. Is any software/hardware required to run SLI (The connector cable I know about)
2. Would two 7900's be an improvement? Or could he SLI with another card to get more power?
3. Running two 7900's would he be required to upgrade his PSU from 350w?
19 answers Last reply
More about dual question
  1. I'm guessing you can get a single card for the same or less than another 7900 that will perform much better with modern feature and support. ?HD 7750

    http://www.newegg.com/Product/Product.aspx?Item=N82E16814102969

    You'll have to look up the power draw might be less than the 7900, certainly less than 2 of them which probably isn't possible with that supply.
  2. HD 7750 peak 43w
    7900 GT peak 48w

    The 7750 is a far superior card in virtually every way.
  3. Thanks for the reply, so newb question but I'm assuming it's possible to hook up two different branded cards? I can upgrade his PSU, a 450w should be okay?
  4. bjaminnyc said:
    HD 7750 peak 43w
    7900 GT peak 48w

    The 7750 is a far superior card in virtually every way.


    Oh it seems you've misunderstood, I'm looking to SLI his current GeForce 7900 with another card if it was possible to replace it I would of done already.
  5. You can but for gaming its not going to help. There is the exception of course of using a nvidia card for physics but that a rather complicated endeavor requiring relatively high end cards.

    Unless you planning on running more than 3 monitors there wouldn't be any reason to keep the 7900 in the case.
  6. konkorfour said:
    Oh it seems you've misunderstood, I'm looking to SLI his current GeForce 7900 with another card if it was possible to replace it I would of done already.



    I am confused. Why can't you replace it?
  7. bjaminnyc said:
    I am confused. Why can't you replace it?


    I tried to get help with this in another thread but found no answer, I upgraded my Graphics a week ago and was planning on giving him my old card since it's better than his current but when placing it into his PC I got no signal. My first thought was a faulty card or I had damaged it but it worked in mine after trying. So I tested in his secondary PCI and it worked but wouldn't boot into Windows unless it was in the primary slot.

    I tried my newer card and that done the same, worked in the secondary PCI slot but not the first and only his 7900 works in the first. I've tried multiple cards and they all do the same, but they are all perfectly working. I've tried different PSU's, RAM and I even updated the BIOS but the only card that works in his PC is the 7900. So unless I buy a new MoBo and see if that's the problem I honestly have no idea what it could be so that's why I thought SLI'ing his PC would be the only option for now because I don't want to spend a lot of money and it still not work.
  8. konkorfour said:
    I tried to get help with this in another thread but found no answer, I upgraded my Graphics a week ago and was planning on giving him my old card since it's better than his current but when placing it into his PC I got no signal. My first thought was a faulty card or I had damaged it but it worked in mine after trying. So I tested in his secondary PCI and it worked but wouldn't boot into Windows unless it was in the primary slot.

    I tried my newer card and that done the same, worked in the secondary PCI slot but not the first and only his 7900 works in the first. I've tried multiple cards and they all do the same, but they are all perfectly working. I've tried different PSU's, RAM and I even updated the BIOS but the only card that works in his PC is the 7900. So unless I buy a new MoBo and see if that's the problem I honestly have no idea what it could be so that's why I thought SLI'ing his PC would be the only option for now because I don't want to spend a lot of money and it still not work.

    That motherboard is on its way out, a second 7900 probably wouldn't work and unless you have another one lying around the effort and cost involved really isn't going to be worth it in the long run anyway.
  9. Mousemonkey said:
    That motherboard is on its way out, a second 7900 probably wouldn't work and unless you have another one lying around the effort and cost involved really isn't going to be worth it in the long run anyway.


    So replacing the Motherboard would fix this problem?
  10. I think SLI on your friends computer is going to be an enormous headache, honestly SLI with 2 cards from that generation would be a hassle on any setup.

    If for some reason there's a problem with your buddy's first PCI slot, you just need to figure out the setting in the bios to make the second slot work. The card should actually work fine in the second slot without changing anything in the bios on most MB's and perform without significant performance loss.

    PCI-e scaling
    http://www.techpowerup.com/reviews/Intel/Ivy_Bridge_PCI-Express_Scaling/6.html

    PCI-e Basics
    http://www.enthusiastpc.net/articles/00003/2.aspx
  11. bjaminnyc said:
    I think SLI on your friends computer is going to be an enormous headache, honestly SLI with 2 cards from that generation would be a hassle on any setup.

    If for some reason there's a problem with your buddy's first PCI slot, you just need to figure out the setting in the bios to make the second slot work. The card should actually work fine in the second slot without changing anything in the bios on most MB's and perform without significant performance loss.

    PCI-e scaling
    http://www.techpowerup.com/reviews/Intel/Ivy_Bridge_PCI-Express_Scaling/6.html

    PCI-e Basics
    http://www.enthusiastpc.net/articles/00003/2.aspx


    I had a look when I was testing the secondary slot but found no option, his board is a foxconn n15235. It has an LED counter and an nVidia fan on the board if I could use the secondary though I could just upgrade the card which would be more ideal.
  12. konkorfour said:
    I had a look when I was testing the secondary slot but found no option, his board is a foxconn n15235. It has an LED counter and an nVidia fan on the board if I could use the secondary though I could just upgrade the card which would be more ideal.

    Are you sure? When I looked all I found was this :-
  13. Mousemonkey said:


    Sorry, I had it mixed up. I meant this one "C51XE":
  14. 590 chipset, that's an old board. I had a similar board (Socket 939) that exhibited the exact same behaviour, I binned it.
  15. Mousemonkey said:
    590 chipset, that's an old board. I had a similar board (Socket 939) that exhibited the exact same behaviour, I binned it.


    So replacing the motherboard should do the trick?
  16. Not worth it IMHO, time for a newer PC.
  17. Mousemonkey said:
    Not worth it IMHO, time for a newer PC.


    Well at the moment he has no money since he's only 14, he has 4GB of RAM, GeForce 210(can still play most games released today so will do for now) he has all of the stuff it's just it wont work on his current motherboard, if replacing it will fix the no signal error then I'd rather do that for him.
  18. If it can run a single 7900 then leave it at that and help him build a new PC for his birthday or something.
  19. Mousemonkey said:
    If it can run a single 7900 then leave it at that and help him build a new PC for his birthday or something.


    I second this. Every piece of hardware in your little buddy's PC is approaching obsolescence for anything other than a power hungry file server.
Ask a new question

Read More

Graphics Cards Computer SLI Graphics Product