I am thinking of doing an upgrade to my system, a fairly cheap upgrade to:
AMD Athlon 64 X2 3800+ Toledo 2.0GHz Socket 939 Processor
ASUS A8V-XE Socket 939 VIA K8T890 ATX AMD Motherboard
Corsair 2GB DDR2-675 XMS2-5400 Xtreme Performance Memory
ATI X1900GT or a X1950GT Video card
will my current PSU work fine for these? I use everything at stock, I dont overclock. I've been browsing the forums trying to find somebody with a similiar setup to see what kind of PSU they use but couldnt find a for sure answer.
No, those ratings are just the total amount of power that rail can handle without failing. Adding 'em up won't get you anywhere. The PSU 101-102 sticky at the top of this section explains how to calculate amperage.
i saw the equation to calculate amps, W/V=A... i checked out the ref list and did some calculations to see if Im using the right numbers and it seems like I am... so I took this equation and popped it into my current PSU and I got 32A... im doing something wrong arent i.. 385 / 12
Well for your PSU, it is 385w max for the +3.3/+5/+12v combined, so you just have to split it up accordingly.
For modern systems I usually give 100w combined for "typical loading" (of non-oc, bare bones sytems) on the +3.3/+5v, rails - so the remainder is available to the +12v. So...
385w-100w=285w, since we have +12v only we can calc for amps...
However... We have a fixed hard limit of +12v@19A or 228w max on your unit. Why is that you may ask? Well look at the total +3.3/+5v is rated for 210w max, which is pretty high... Which was normal for a single-rail "legacy" ATXv1.3 unit way back when the +5v fed the motherboard for the CPU power. "Modern" systems have an ATX+12v 4 or 8 pin CPU connector, so the demand for +12v increased while the +5v decreased. Hence, ATX v2.x was born and dual +12v rails became standard.
So your power supply is an excellent legacy replacement, or maybe if you are going to perform a dual PSU mod that would work well since you are effectively adding a "second rail" via another power supply.
you both misread, I was trying to explain why older atxv1.3 units with a single +12v rectifier won't work in a modern system but work well for older boards that feed the CPU from the +5v - the unused potential that would normally be available to a dual-12v rectified system just isn't there.
yes that unit will not have the capability to support the 24A on a single rectifier but if it had a second rail of 15a max / 19a peak then it would be no problem. I use 100w since I measured my system bare-bones at 80w for the +5/+3.3 so just overstating slightly. Have not tried on a ddr2 system as of yet but should be similiar unless you are running a disk array and/or memory overclocking.
Perhaps you just didn't read the second paragraph at all and just the 24A part - so it was worded poorly after I re-read it
If we use the actuall numbers from the PSU then we get, as mentioned above, 385-210=175. So 175/12=14.58A.
Using this logic, the corsair 520w is only good for +12v@30a... The corsair 520w label, states:
To test your theory, let's omit the +12v@480w and subtract the -12/+5vsb to get the +3.3/+5/+12
And finally, take out the +5/3.3 max... +12v=495w-140w=355w or 29.5A max
IMO that is a bit low.
Using my true 80w measured for the +5/+3.3, we get 495-80=415w/34.6a
which is a much more "realistic" attainable +12v power when "typically loaded"
The capacity may be there for +12@40A however that does not give much room for the rest of the system. However, that would make it an excellent dedicated GPU PSU with that much on the +12 and so little left over for the other rails