Yes, I know it's kind of a POS, but the price was right.
Except it probably wasn't right. Crappy rail topology and connector count(1)
basically make this PSU a three GPU capable device thus degrading it to a 650W level.
Is there any excuse for not fitting a 1kW unit with even one sodding PEG 8-pin connector???(2)
A decent 800W unit would have no problem with powering four 5850 cards which this PSU just can't do without some hardware hacks and thus voiding your warranty.
A 5850 is a 150W-ish card. 150W at 12V is 12.5A.
A PEG 6-pin connector is rated for 75W by the ATX spec.
Without soldering in additional connectors the best you can do is:rail2 -> a single 5850 card
rail4 -> a single 5850 card
rail3 -> a single 5850 card
using two double molex -> one PEG-6 connector
adapters (be sure to have read this topic
Each of those rails is only loaded in 62% but there are no wires to fit in a fourth card.
One option I thought I might do is splice a second PCIe connector onto each PCIe rail...
We're talking of a crappy PSU here - isn't it better to sell it off on e-bay and purchase something decent? Is it worth all the hassle?
If you choose to proceed with your wacky plan, your best bet would be to solder in one PEG-6 connector to rail2 and one to rail4 and run the fourth card off these:rail2, rail4 -> a single 5850 card
Whether you do so by
(1) clipping off one PEG-6 connector and soldering/using wire nuts to attach two PEG-6 connectors in its place, or
(2) opening up the PSU and soldering in some additional wiring fitted with a PEG-6 connector (e.g. recycled from a dead PSU)
is of no great importance.
The first option is the quick-and-ugly but easy path. The second, while more labour intensive, is the elegant solution.
If you go with wire nuts, make sure to twist all those wire strands firmly together - the last thing you need is a short circuit taking out your cards.
Remember, however, that I take no responsibility for whatever damage or physical harm you might cause by messing with your PSU.
Whether it's you or your mining rig that gets zapped, whether your PSU, your house, or your neighborhood burns down, don't come crying here.
I'm not too worried since I expect the draw at the wall of the system to be in the 700W range, but I am wondering what is the best way to configure the system for mining.
Simply put, without voiding your warranty you can't. That's what you get for getting lured with the price.
(1) :chuckles: It might only have four PEG-6 connectors but hey, it's got not one but two floppy connectors, fancy that!
You can hook up two floppy drives and copy floppies in a most convenient fashion!
(2) the only explanation I can come up with is that those 12V rails really can't deliver the promised 20A:
A PEG-8 connector (rated for 150W) and a PEG-6 connector (75W) combined might require up to 225W (18.75A) from the rail.
If the manufacturer didn't feel confident that their PSU was capable of actually delivering such loads, they would naturally go with two PEG-6 connectors.