2nd PSU
 

I would like to run 2 PSU's on my i7 setup however I am unsure of how to get the second one to turn on without plugging it into a mobo. The power supplies are PC Power and Cooling 1200W ESA. Link here to manual http://www.pcpower.com/downloads/Tur...anual_3835.pdf I am wondering what wires I would need to jump to get the PSU to turn on.

Thanks

You can either jump the green wire to any of the black wires on the second PSU and turn it on manually.... or get something like this...

http://www.performance-pcs.com/catal...ducts_id=21193

+1 to the adapter that allows second one to get the "kick on" signal

I just took some spare wire and popped it in the tops of the 14/15 pins back when I ran dual PSUs

Make sure you have some 3.3 and 5v load on the second PSU

(like run your sata devices off of it.)

Well my plan was to run the CPU power and hard drives off one PSU and the GPU off the second PSU. Will this configuration work or would I be better to run the GPU's with the HDD and leave the PSU for the CPU on the other PSU.

If your going to split it up I would use the main PSU for the CPU and Board and power everything else with the second PSU.

Yah.

Back in hte day if you did not have load on the 3.3/5v rails, it could cause problems. Dunno if that is still the case. Which was why I recomended running sata drives off the second PSU (the real 5 wire sata power not hte molex adapted kind) A lot of PSU comapnies run only 4 wires to the sata ports, these are "adpaters" not really sata power plug. Must have the 5th line for 3.3v. (Without it I do not think you can hot swap the sata drives.)

Paper clip if anything:

http://img206.imageshack.us/img206/6893/dscn00691bn.jpg

The paper clip type method is best IMO and you can actually setup a switch to use so it's convenient and looks nice (if you care). The reason I say this is that when you add that adapter cable in you of course are increasing the number of connections and increasing overall resistance and potential points of failure blah blah.

The biggest reason I would say to stay away from the adapter is that the 3.3v rail runs through the 24 pin to supply power to your RAM, any hinkiness in that ckt will degrade your ability to stablize your RAM and could even cause damage.

I'm using the adapter with good results. Not to say the negative issues pointed to aren't valid. I would consider just running a couple of wires beeing just as good, if not better than the adapter, as it keeps one big connector out of the loop.

One advice along the road tho, to avoid grief: run your CPU, board and boot devices (any disk/optical you wanna boot from) off the primary PSU, as the second PSU will have a split second delay in powering up and may spin up the drives a little to late for the BIOS to detect them. I run the gfx and most of the fans (only one of the cpu fans run of the mobo, the rest from the second PSU via fan-adapters)
Pressing the reset switch after initial powering up will ofcourse fix the delay in surge from the second psu, and you will have a clean regular boot :)

I've been using the very adapter for over a year now, no issues so far.

That adapteris the same method I used on mine.

Insert wire into top of adapter on both PSUs.

What the heck, your running 2 1200w power supplies. If your actually using the load, you might run into circuit problems and trip the circuit breaker in your house.

1200W should be good for quad cpu, 5ghz cpu and a lot of drives, especially a pc power and cooling.

I think what a lot of the big guy or well known names do at times is use two large PSU's so they can provide as clean as power as they can get. One PSU powers the GPU's and the other for the rest.

I don't really know who that effects things, just something I have seen.

I have often wondered how pieces of equipment handle two different power sources and if they mix well with out any problems.

Example...

A GPU has power coming from PSU #2 through the main power connectors.
It also gets power and signals through the PCIe expansion slot from PSU #1.
How that effects ground and signals I don't really know.

Talking to Peter last time he mentioned that some psu's need a balanced load on the rails or it can fail. Suggested putting some load on the other rails as well to avoid problems.

Oh yah i forgot about that too. That is probably a bigger problem now than the 3.3/5v rail loads (only need a 1AMP draw on thoses)

Not all PSUs have a problem with the 12v load issues
OW over at jonnyguru brings this up quite often in his reviews. Single rail or split rail psus should not have a problem with this though.

I can handle the house hold electrical issue being a master electrician. I was just curios if it would make a difference on taking some stress off the PSU. The system I would use it on is Classified with the 975 in the 4.8 to 5 Ghz range 2 x 4870x2 OC'd and 4 seagate 120GB drives plus fans. I suppose I could calculate the load to see how close to maxing the PSU out I am.

Just wanted to chime in.... I have used all these methods with great success. In the end what you like is what will work.

I favor the connector plug. Cleaner, and easier to trouble shoot....

The real reason I posted in this thread.....

Please keep in mind a few items....

1. Unless your using the same model PSU and/or it is not modular ignore this.... If not please do not use one modular cord from one PSU with the other. Or any of their adapters for that matter. Sadly I made this mistake and lost a PSU and MOBO in the process.
2. If your using a MOBO with two 8pin 12volt connections.... Please do not plug one 8pin 12volt connection from each PSU to the one MOBO.. I believe I lost a Classified doing this! According to EVGA techs.... Only use the two NON adapted 8pin 12volt connections from the single PSU that the manufacturer supplied.
3. I found that running two PSU's while allowing for a much cleaner power foundation for the system, it did push my circuits to the limit. I popped my UPS and breaker a lot.... And I am wired very nicely with serious UPS to boot.... In all reality I even went as far as researching for a 240volt setup to run my main system with.... Never found the right one for my needs though.....

Good luck and have fun!

That PS can definitely handle that load. If this was a HX1000, I would be worried, but the pc power and cooling 100A single rail with a 115A maximum should handle it without problems.

I thought single rail had no balancing issues Kal-el, I can imagine a problem popping up if this was the hx1000, because a heavily overclocked core i7 and a 4870x2 load would have to be on one of the 40A (since it has two rails) rails, but this is a massive 100A rail.

Also this type of power supply I remember doesn't really have any ripple as it is a top quality server power supply.

Also one more thing is i think two 1200 is a bad idea, is because efficiency is going to fall through the roof when this thing is idling(of course the OP likely not one to care for this) when this thing is running at like probably 10-15 percent of the load of the power supply. Thats because most PS are not terribly efficient when they are only using this much of their capacity. The silverstone ST1500 sounds like the perfect power supply for this build and its not nearly as loud as a turbo-cool and for a high power build like this, I think multiple rails are not bad.

I understand about the efficiency also the power factor is usually poor on lightly loaded equipment. I run into this alot on large UPS systems. They will generally induce harmonics and the PF and efficiency suck when lightly loaded.
I guess I wil just stick to one PSu for each board. I have a R2E w/965, Classified w/ 975, and REX with QX9650 or E8600 or E8500. Looks like I need another PSU for the 3rd set up.

I toasted a ST1200 Silverstone, thats how the topic came up about possible balancing issues.

I short circuit green and black wires and it works grate