boggy Posted April 19, 2006 Posted April 19, 2006 As for thread title, do you think i can run 2 7900GTX in SLI on my rig? Do you think my PSU will likely fail? Share this post Link to post Share on other sites More sharing options...
Nehil Posted April 19, 2006 Posted April 19, 2006 I don't really know but this might help you. And this. Share this post Link to post Share on other sites More sharing options...
EdLSmith Posted April 19, 2006 Posted April 19, 2006 According to info I have available, it is good as gold for SLI with OC. It is listed in the approved list. Good luck. Share this post Link to post Share on other sites More sharing options...
boggy Posted April 19, 2006 Posted April 19, 2006 Have a look at this page: http://www.slizone.com/object/slizone2_build.html My PSU is NOT listed as certified for dual 7900GTX or 7800GTX 512 while it is for all other SLI configurations. On the other hand according to XBit labs there should be no problem even with a good quality 450W PSU. Share this post Link to post Share on other sites More sharing options...
Raphie Posted April 19, 2006 Posted April 19, 2006 SLI certified is costing a lot of money, so i can imagine that there are quite a few PSU makers who don't care about the logo. Share this post Link to post Share on other sites More sharing options...
red930 Posted April 19, 2006 Posted April 19, 2006 Have a look at this page:http://www.slizone.com/object/slizone2_build.html My PSU is NOT listed as certified for dual 7900GTX or 7800GTX 512 while it is for all other SLI configurations. On the other hand according to XBit labs there should be no problem even with a good quality 450W PSU. XBit labs is running an SLI 7900GTX rig with a 450W PSU? Can you provide a link to the rig? Share this post Link to post Share on other sites More sharing options...
RGone Posted April 19, 2006 Posted April 19, 2006 ^^ me too!!! What he said... RGone... Share this post Link to post Share on other sites More sharing options...
watsonte Posted April 19, 2006 Posted April 19, 2006 Is there enough room on an SLI-DR For two 7900GTX's? and if there is how many millimeters of space is there between the cards? Share this post Link to post Share on other sites More sharing options...
Wicked_Wish Posted April 19, 2006 Posted April 19, 2006 It should fit but it might be kinda tight. And I don't know about your PSU, I would say it should work, but just to play it safe I would get something stronger like a Fortron Epsilon 700watt, or OCZ is comeing out very soon with a new 600 and 700 watt power supply, or if you have the money a PC P&C 850watter! You can try it but idk. I also want to see that link to the 450watt sli setup too. Share this post Link to post Share on other sites More sharing options...
boggy Posted April 19, 2006 Posted April 19, 2006 They tested the wattage drain of the various cards and say that even for a dual 7900GTX a quality 450W PSU is enough. See here: http://www.xbitlabs.com/articles/video/dis...e7900gtx_6.html but in the the test rig they used for benches there is a 620W PSU (see here: http://www.xbitlabs.com/articles/video/dis...e7900gtx_8.html). As for the space btween cards, well they should fit. If my two 7800s are now fitting with zalmans the new 7900s will fit either (will replace the standard cooler). The space btween cards is tight but I have arranged two fans blowing directly on the side and my cards temps are never over 65. That's not bad if you consider I'm running both cards @470 core 1200 mems. Share this post Link to post Share on other sites More sharing options...
Wicked_Wish Posted April 19, 2006 Posted April 19, 2006 That's interesting, seems possable but I don't know if I would try it. I still like seeing though how the X1900XT is super fast, has this advanced ring-bus memory architecture, 48 pixel processors (theoretical, I still don't fully understand how ATI does this), and is a power-hungry monster; yet the 7900GTX ties it, crushes it, or at worst is like 10 fps behind it in every test, and it does all this buy using very little power. It seemed too that acording to that bench, almost all of Nvidia's fillrates where through the roof as ATI's droped off. Share this post Link to post Share on other sites More sharing options...
red930 Posted April 19, 2006 Posted April 19, 2006 Note that the new card consumes the largest share, about 45W, from the PCI Express x16 slot and only about 36W from the external power line. The remaining 3W are consumed from the +3.3V line. For comparison, the Radeon X1900 XTX is almost the same load on the graphical slot, but it sucks in as much as 72W from the external +12V line! Thus, though an elite graphics card, the Nvidia GeForce 7900 GTX has a very modest appetite and doesn’t require a high-wattage power supply even if you are going to put two such cards into your system case. A good-quality 400-450W PSU will be quite enough. Let's do the math using their measurements... 45W/12V=3.75A 36W/12V=3.0A 3W/3.3V=0.9A Grand total of card = 7.65A, times two cards = 15.3A for SLI. Now the very best 450W PSU available that I know of is the FSP AX450-PN version 2.0 for $50.99 from the egg. Let's look at the specs on this PSU... +3.3V@30A, +12V1@18A, +12V2@18A Now remember that 12V2 is dedicated to the CPU so that leaves just the 12V1 rail to supply current to the board and accessories like an SLI setup. So, we have 18A minus the 15.3A for the SLI cards leaving a grand total of 2.7A for the rest of the 12V needs. Am I missing something? Would any of you guys want your PSU pushed so close to the edge on a daily basis? Share this post Link to post Share on other sites More sharing options...
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