Looking for 750w+ power supply w/ 4 x 8 pin PCI-E

[ccassityabr]

I am looking for a 750w+ power supply that has 4 x 8 pin PCI-E for around 50 dollars. I an needing to power two Sapphire R9 Nitro Fury Cards for mining, which pull 250-300 watts each.

If this is not possible for the price, I am considering the use of adaptors, however I am almost certain Molex adaptors would not work. Is this correct? Is it safe to use 6 to 8 pin pcie adaptors?

Any advice would be appreciated!
System build: https://pcpartpicker.com/list/6yJqYr

 

[volkgren]

With a 24/7 100% load situation you definitely don't want to use molex or 6 to 8-pin adapters. I think you should increase your budget for a power supply given your demanding needs. Better to get a good quality power supply than to have a cheap one short out your whole system and take some other parts with it.

This isn't exactly the power supply I'd recommend for your situation, but I would recommend it over any $50 750W power supply with respect for your budget. It's on sale for this price and it has 4x 8-pin PCIe.
Power Supply: Corsair - CX (2017) 750W 80+ Bronze Certified ATX Power Supply ($64.99 @ Amazon)

Other better options.
Power Supply: Corsair - TXM Gold 750W 80+ Gold Certified Semi-Modular ATX Power Supply ($79.99 @ Newegg)
Power Supply: Corsair - TXM Gold 850W 80+ Gold Certified Semi-Modular ATX Power Supply ($89.99 @ Newegg)
Power Supply: Corsair - RMx 750W 80+ Gold Certified Fully-Modular ATX Power Supply ($99.98 @ Amazon)
Power Supply: EVGA - SuperNOVA G2 750W 80+ Gold Certified Fully-Modular ATX Power Supply ($99.99 @ Amazon)
Power Supply: SeaSonic - FOCUS Plus Gold 850W 80+ Gold Certified Fully-Modular ATX Power Supply ($99.99 @ Newegg)

*I would strongly encourage you to go with one of the better options. They are rated for higher temperature operation.

 

[Mark RM]

If it's just two cards get two smaller high quality PSU's and tie them together.

 

[jankerson]

For those cards you will need more than a 750W PSU and anything around $50 would be worth buying and would be a fire hazard.

You need to raise your budget a lot, double what you are thinking to get a PSU to handle both of those cards.

 

[volkgren]

According to reviews total system power with a single R9 Fury was 335W. So the GPU alone must be around 250W or less. I'd say 750W would work but I would personally get the SeaSonic 850W right now if you can because it's on sale.

Plus mining people tend to lower power consumption as much as possible, which is something I would encourage OP to do.

And two smaller high quality power supplies would still cost more than $100.

 

[jankerson]

According to reviews total system power with a single R9 Fury was 335W. So the GPU alone must be around 250W or less. I'd say 750W would work but I would personally get the SeaSonic 850W right now if you can because it's on sale.

Plus mining people tend to lower power consumption as much as possible, which is something I would encourage OP to do.

It's more than 250W, a lot more, was one of the most power hungry cards around and still is.

A good 850W PSU would be min for 2 of them, one that can actually take that load 24/7/365.

Something like a RMX 850W or Prime Gold 850W.

 

[Mark RM]

The thing is when you mine, normally you run the motherboards off whatever crap is lying around, even pico PSU's. Then you buy a cheap ass server supply with a plat rating and a breakout board for your cards, the concept being , as many as you can from one PSU and clean stable power.

 

[volkgren]

Okay I was looking at the lower test, total system power was 363W running Crysis 3. https://www.anandtech.com/show/9421/the-amd-radeon-r9-fury-review-feat-sapphire-asus/17

I suppose it could be more under certain circumstances such as overclocking, etc.

And I still agree OP needs to increase budget by at least double.

 

[volkgren]

The thing is when you mine, normally you run the motherboards off whatever crap is lying around, even pico PSU's. Then you buy a cheap ass server supply with a plat rating and a breakout board for your cards, the concept being , as many as you can from one PSU and clean stable power.

That would be the best way to go about it. Only problem is most small-time miners have their rigs inside their house. So a server power supply would be considerably loud to live with. If you had an extra room to close off of a basement or something it wouldn't be much of an issue.

 

[volkgren]

I personally think the TX850M is a great unit (aside from semi-modular), at a good price. JohnnyGuru said his had Platinum efficiency at room temp.
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story6&reid=520

And the SeaSonic FOCUS is also a great unit.
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story6&reid=524

The RMx and PRIME series are better, but not that much better if you're on a budget.

 

[Mark RM]

That would be the best way to go about it. Only problem is most small-time miners have their rigs inside their house. So a server power supply would be considerably loud to live with. If you had an extra room to close off of a basement or something it wouldn't be much of an issue.

I bought a small public school for my miners, but I keep about 20/30 cards here at the house so I can experiment with BIOS/mining software/different block chains. Everything is in the basement, we really don't hear it. I do get what you're saying though. It's fine in winter anyhow, the excess heat go to heat the house and it's been below -30 at nights.

 

[volkgren]

I bought a small public school for my miners

😀

I have 8 cards in my house right now. It has turned off cold 20-30F (I live in southern US) and I'm wishing I had more haha.

 

[ccassityabr]

Thanks for the input everyone!
I decided to go with Volkgren's suggestion of the Power Supply: Corsair - TXM Gold 750W 80+ Gold Certified Semi-Modular ATX Power Supply ($79.99 @ Newegg). Many thanks this is exactly what I was needing.

The reason I am not going with a higher power supply is because both graphics cards have an option where you can switch to an economy bios making them consume >250 watts. After much testing and overclocking in my main rig, I found no significant differences in the hash rate or gaming performance between the two bios options. So I will leave the cards in economy mode and will they will not be overclocked.
Thanks again everyone!