Wally's World Posted October 16, 2006 Share Posted October 16, 2006 Okay, don't laugh but I want to make sure I got this straight. Later this week I will be purchasing an EVGA 7900GS 256MB PCI-E video card for my system. My PSU is an Antec SmartPower 450W with 15A and 17A on dual 12V rails. Now I read here in this forum that my PSU will be enough to power the new card along with my CPU (Athlon 64 3700+) and two hard drives, but I wa told that I need to make sure that the video card is on a separate rail than the rail with the CPU. The truly and really stupid questions I have are: How do I make sure that the video card power supply is on the other 12V rail from the CPU? Is it just a matter of plugging in the 6-pin power cord into the video card? In other words, how do I make sure the video card is one a separate 12V rail? I am lost when it comes to PSU's so that is why I am asking this very, very basic question. Many thanks for all replies. 0 Quote Link to comment Share on other sites More sharing options...
Schrullenhaft Posted October 16, 2006 Share Posted October 16, 2006 A power supply with two +12V 'rails' and a 6-pin PCI-e power connector for your videocard, is most likely wired with the 4-pin (square) power connector having 12V2 (for the CPU) and all other 12V connections as 12V1 (24-pin ATX, 6-pin PCI-e, 4-pin molex, SATA power connectors and 4-pin floppy power connectors). This is the standard for ATX12V v.2.0 power supplies, which Antec claims compatibility with. Antec does not specifically say how the rails are wired in their literature/web site. When your power supply has three 12V rails, then one will be dedicated to the 6-pin PCI-e power connector(s) in addition to the wiring above. With 4 12V rails, each 6-pin PCI-e connector has its own rail (obviously geared towards dual-GPU setups). Here's a little more on the subject of multiple 12V rails. [ October 18, 2006, 10:42 AM: Message edited by: Schrullenhaft ] 0 Quote Link to comment Share on other sites More sharing options...
Redwolf Posted October 18, 2006 Share Posted October 18, 2006 The PSU should have a diagram about which connector is on which rail, otherwise it is of questionable quality anyway. It is fair to assume, however, that if the PSU has one 6-pin PCIe and one 4-pin EPS12V they will be on separate rails if the PSU has more than one rail. That's all you care about. Modern harddrives don't matter much, they are less than 10 watts and draw from 5V. 0 Quote Link to comment Share on other sites More sharing options...
Wally's World Posted October 18, 2006 Author Share Posted October 18, 2006 Thanks to both of you for your replies. 0 Quote Link to comment Share on other sites More sharing options...
Wally's World Posted October 19, 2006 Author Share Posted October 19, 2006 Schrullenhaft and Redwolf: Again, many thanks for your reply. I bought the BFG 7900GS OC PCI-E and installed it with no problem. It doubled my normal FPS from my old 6600GT AGP. 0 Quote Link to comment Share on other sites More sharing options...
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