Is my power supply two weak?

sweave

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=2132071&CatId=1483

is the power supply i purchased for my new build

but then i noticed on the higher end gfx cards for example
http://www.newegg.com/Product/Product.aspx?Item=N82E16814133194

it requires 30A at 12v rating

now mine has the specs of 12v1 at 18A and 12v2 at 20A
and i notice that that gfx card (as well as many others) has two power slots on it.
so does max combined (dual rail) fit in that spec for the vid card or does each 12v rating have to be over 30A?

edcentric

sigh, This is one problem with split rail PSUs. You have an 18A and a 20A, what if your loads are 5A and 24A? It is well under your limit (29A vs 38A), but there is no way that you can power it.
You need to figure out what each individual load is and see if you can get them to match your PSU outputs.
I don't know if you can split the inputs for the video card.

Park_7677

Read this first: http://www.playtool.com/pages/psumultirail/multirails.html

There is no PSU rated at 30 amps for a single 12V rail and within ATX spec. The maximum ATX spec is 240 VA (volt amps). The max amps for a 12 volt rail is 20 amps (12 x 20 = 240 VA). Keep in mind that the PSU may be outside of ATX spec but not likely.

That PSU should be fine. Why? Because the ATX spec says 12V1 powers everything expect CPU and the 12V2 is for the CPU only (most likely the 12V2 rail only goes to the 4-pin 12V plug you stick in the motherboard). That PSU claims SLI ready meaning they have tested your worries about "needing" 30 amps on the 12V rail. In reality most "multi rail" PSUs are a single rail split within the power supply itself and the 30A on 12V rail the video card is referring to the total 12V rails. (you would have 38 amps)

Now that I've confused everyone more and butchered what the link above is saying READ THE LINK ABOVE to decipher what I said :o

PS. Even a 1000W PSU does not list a 12V above 20 amps, but rather 4 rails at 20 amps each.

sweave

Thank you for your reply Park-7677.
Read a few pages there (and one mild migraine later) so it was fairly helpful.
what i understood was that the vid doesnt draw the full 30 amps for itself but rather it is a guide =\

so if i were to run a single vid series 8 vid card would that work?
and that vid card i linked to in the 1st post is not the one i was planning on getting as it is 400 above my price range (its priced 600 or nearly there i think).

what i was planning on was something like this instead
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3051802&CatId=1560

Thrax

That'll work. Just make sure you read the manual on your PSU to identify which cables lead to which rail. Hook all your drives up to one, then the GPU up to the other.

edcentric

I have looked at the documentation with a few video cards and have never found one that actually tells you what the max load from each power source is.

Park, Do you want single rail PSUs? Look at PC Power&Cooling. Their 510W has 34A , the 610W is 49A and the 750W is 60A, all on single rails.

dnorf87

Or you could get a good power supply that isn't overrated (such as the one you linked to), that acts as if it's a single rail unit...such as the Corsair HX620W, or even the Antec TruePower Trio 650w.