Using multiple PSUs - Does anyone actually do it?

[Garr255]

As I said in my other post here: https://bitcointalk.org/index.php?topic=60928.0
I am going to attempt to use an older PC to mine, using PCI > PCI-e risers, assuming they do exist, I have yet to find them, and wouldn't doubt that they don't.
I also will be having a power issue if I choose to add more than one card.

The current PSU is 250W, which I hope I'll be able to leave powering the lot of the computer.
I plan to use the 500W PSU I have laying around to power just the GPUs and the powered risers to them. (Yes I know you need to start both PSUs simultaneously and how to do it)

My main question is: What are the dangers of doing this, and if any, how to prevent them.

I do have limited resources as a 16 year old, so building a new rig really isn't an option. (Why else would anyone go to this much trouble to convert an old PC into an unstable mining rig?) For fun maybe? Whatever.

I do take criticism positively, so if you think this is just plain stupid, please, let me know.

Thanks for the help,
Garrett

[ZodiacDragon84]

Using dual psu for 4890 rig. I have a 500w I acquired, and a 300 watt running the system. I have all 3 12v rails on the 500w plugged into my molex to PCIe adapters, and I just leave the card plugged in and running all time. Fires right up when the main psu kicks power through the bus to the 4890, and everything mines in happiness for the most part

[yjacket]

Using dual psu for 4890 rig. I have a 500w I acquired, and a 300 watt running the system. I have all 3 12v rails on the 500w plugged into my molex to PCIe adapters, and I just leave the card plugged in and running all time. Fires right up when the main psu kicks power through the bus to the 4890, and everything mines in happiness for the most part

Why are doing that? Does the 4890 even cover power costs? I used one, as it was my g pu the time, when bitcoin was $20. It would regularly hit 100 C.

[Transisto]

Lots of fail in your hardware, the 4000 series is dud for mining.

I was getting 70mhs out of an 4870, same power consumption as 5850 for 370mhs

70 < 370

[yjacket]

Lots of fail in your hardware, the 4000 series is dud for mining.

I was getting 70mhs out of an 4870, same power consumption as 5850 for 370mhs

70 < 370

No need to be a dick.

[rjk]

Lots of fail in your hardware, the 4000 series is dud for mining.

I was getting 70mhs out of an 4870, same power consumption as 5850 for 370mhs

70 < 370

No need to be a dick.

He's not, its correct. However I remember they guy with the 4000 series using solar, so he doesn't care about power usage. Although the backup battery would last longer if the card was powered down.

[ZodiacDragon84]

thanks for reading my other posts about solar RJK. as i have mentioned in other posts, the 4890 does other tasks too, and I hit 100 Mhash/s with it only hitting 70c.

[jjiimm_64]

(Yes I know you need to start both PSUs simultaneously and how to do it)

I have a few rigs with 2 psus.  you dont have to start them at the same time.  the psu that has just gpus on them should be running first.

[likuidxd]

How much is your time worth to you?
I ask because your risers will give you headaches, your PSU(s) will give you headaches, your case will give you headaches...
It's probably just going to be worth it to spend $150 and buy a used board/cpu/ram combo and build yourself a new used rig. You'll be happier with it and you'll better understand what is going on with it when something breaks, it will.

That said:

Using 2 PSU's is fairly safe. I have run 2 in all my rigs in an always on setting, crossed the switch cables(green/black). I did this for about 8 months until I bought a pin removal tool and spliced the two together. I always worry about fire, not because of the PSU necessarily but because it's very hot, always on and it draws a ton of power.

[jjiimm_64]

Using 2 PSU's is fairly safe. I have run 2 in all my rigs in an always on setting, crossed the switch cables(green/black). I did this for about 8 months until I bought a pin removal tool and spliced the two together. I always worry about fire, not because of the PSU necessarily but because it's very hot, always on and it draws a ton of power.

I just use a paper clip, or other little piece of metal to stick into the green/black pins in the middle of the plug.  (there are pics online about this)

[Garr255]

Thanks for the replies.

[fb39ca4]

You can use a cable like this between the 24 pin connector of the main PSU and the motherboard, and then plug the 24 pin of the secondary PSU into the thingy hanging off and both will start at the same time.

[jjshabadoo]

It has given me nothing but headaches and I highly recommend against it, but guys like Jimm_64 have 30 GH/s farms and he uses the paper clip thing and it works fine for him. I used lian li PSU adapters and they have still driven me crazy.

If you're only working on a one or two card rig then go for it. If you want to go for a rig with 4+ cards I say avoid it like the plague.

[Transisto]

How much is your time worth to you?

HD4890 = This *10

[BCMan]

How much is your time worth to you?
I ask because your risers will give you headaches, your PSU(s) will give you headaches, your case will give you headaches...

And also ATI/AMD with still not fixed on Win7 x64 fucking cpu load bug will give you headaches.

[xanadu]

How much is your time worth to you?

HD4890 = This *10

I am struggling with this problem, 5970's pull ~230W each when mining, what PSU are you using that will run 4x 5970's and the motherboard without issues?  I really need a better PSU solution!

Thanks,
-X

[jjshabadoo]

seasonic x1250 will do it.

[fourd00rgtz]

I haven't yet for mining, but had a folding rig running 4x9800gx2's on 2x650w corsair psu's up until 6mo ago. They ran like a charm for nearly 3yrs, their production per watt kinda got obsolete so I swapped it into a dual 5970 mining rig on a single 750w, gotta love the k9a2-platinum, still ticking.