PSU power problems on a powercolor HD4870 1GB PCS+

burtzz

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Nov 7, 2008
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Hello

I'm realy worried about my PSU, if its capable to feed a powercolor hd4870 1GB PCS+. My PSU has only 1 pci-express power cable, and as some of u know, the graphic has 2 connectors,and rly needs 2 feeders on her. So im going to buy one of those adaptors that turn one the Molex(the 4pin ones I think) to another pci express cable. Or the one who turns the pci express cable connector to two connectors.

I have a http://www.lc-power.com/htm/products_detail.php?lang=2&h_id=1&u_id=2&a_id=49 PSU. It quite a recent model.

this are the Amperes values straight from the PSU manual
Type: ATX PSU
Power: 550 W
Input Voltages: 230 V
Input Frequency Range: 50 Hz
Input Current: 4 A
5V Max. Current: 40 A
12V1 Max. Current: 16 A
12v2 Max. Current: 18 A
3.3V Max. Current: 35 A
-5V Max. Current: 0.5 A
-12V Max. Current: 0.8 A
5VSB Max. Current: 2 A

Since im going to use one of those adaptors, my PSU has to have a good Amperes values on the 12V rails. (at least thats what I read). Seems it works like this: 12v1+12v2(16A+18A) = 34 A.

Its this enough to feed this graphic beast?
Im rly worried about this because the only feedback I got so far,(only from 1 person) its negative, "the PSU has not suficient Amperes on 12V (or its on the very top limit) to be able to power the graphic." "And turning on the graphic on that PSU may cause some damage".

Any opinions from someone inside this matters please?
 

Zecow

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Oct 29, 2008
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I am powering my 4850 crossfire with a 550watt psu. It should run fine. But I do not think that this psu is a quality psu. I really doubt the amps on the 12v rails and the watt output are as stated. Might be 1 burst and pooop goes your card/psu. invest a little more - all your components are powered by the psu - its really important to pay a premium for it.

 
You cant just add up the rails it works differantly. Does the PSU list what the Watts for the rails compined is ? or if not then the watts for the 5 and 3 v rails ?
The problem is that only the very best quality PSU's can b etrusted to tell the truth when stating the available power.
Very roughly working back from the numbers you have given. If the 5v and 3.3 v rails claim to supply 40 and 35Amps is taken on trust that would leaev about 20 for the + 12v rail.
Post those wattage numbers if you can and we will see if it adds up.

Mactronix