- Oct 19, 2014
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I just ordered an XFX R9 290X, my power supply is an Antec EarthWatts EA650 and my processor is an FX-8320. The only reason I'm really asking the following question is because I don't really know what all exactly is powered by the 12v rails from the power supply. According to my math, I should be okay to power the 290X but I just wanted to double check and get some opinions here.
Power supply specs are as follows:
+3.3V@25A, +5V@25A, +12V1@22A, +12V2@22A, +12V3@25A, -12V@0.5A, +5VSB@2.5A
So, I have a total of 69 amps on the 12v rails (850 watts, assuming no voltage loss). I've read that the 290X draws about 300 watts continuous which is 25 amps (Which I hope the 12v3 25A rail is the PCI Express rail). The processor draws 125 watts continuous which is roughly 10-11 amps. Besides the fans and maybe the hard drive, I don't know of anything else to account for, but it leaves me with about 30amps/350 watts for the motherboard, fans, hard drive, or whatever else runs off the 12v rails.
The 290X says that it recommends a minimum of a 750 watt power supply, but the 12v rails on my power supply total 850 watts, even though it's rated at only 650 watts. I just wanted to check here to make sure that, under my assumption, the 12v rails are what to look at when powering a video card. I know not to always trust advertised power ratings and I just wanted to get opinions here on what I should expect, based on the math (Volts * Amps = Watts) because obviously some power supplies are underrated and some are overrated, and according to the posted specs, mine seems to be underrated, I hope...
The card requires an 8-pin and 6-pin PCI-Express power plugs, which my power supply has, but do the 8-pin and 6-pin run off the same rail, and if they do, would it be better to use the supplied molex to 6-pin PCI-Express adapter to even out the current draw across two rails instead of pushing one rail to the maximum?
Power supply specs are as follows:
+3.3V@25A, +5V@25A, +12V1@22A, +12V2@22A, +12V3@25A, -12V@0.5A, +5VSB@2.5A
So, I have a total of 69 amps on the 12v rails (850 watts, assuming no voltage loss). I've read that the 290X draws about 300 watts continuous which is 25 amps (Which I hope the 12v3 25A rail is the PCI Express rail). The processor draws 125 watts continuous which is roughly 10-11 amps. Besides the fans and maybe the hard drive, I don't know of anything else to account for, but it leaves me with about 30amps/350 watts for the motherboard, fans, hard drive, or whatever else runs off the 12v rails.
The 290X says that it recommends a minimum of a 750 watt power supply, but the 12v rails on my power supply total 850 watts, even though it's rated at only 650 watts. I just wanted to check here to make sure that, under my assumption, the 12v rails are what to look at when powering a video card. I know not to always trust advertised power ratings and I just wanted to get opinions here on what I should expect, based on the math (Volts * Amps = Watts) because obviously some power supplies are underrated and some are overrated, and according to the posted specs, mine seems to be underrated, I hope...
The card requires an 8-pin and 6-pin PCI-Express power plugs, which my power supply has, but do the 8-pin and 6-pin run off the same rail, and if they do, would it be better to use the supplied molex to 6-pin PCI-Express adapter to even out the current draw across two rails instead of pushing one rail to the maximum?
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