You cant connect 6 GPU's on 1 PSU. There is no PSU on the market with 12 PCIe connectors.

EVGA has 9 connectors. You can run 4 GPU's and if you use a cable-mod (CPU to PCIe) you can run 5 GPU's.
(SuperFlower is the same as EVGA. If you dont need the 2000W, better go with EVGA!)

Seasonic Prime Gold 1300W ATX 2.4 (SSR-1300GD) has 10 connectors. With good undervolt you can run 5 Radeons. But with every energy-spike, every GPU-reset, everything which dont stay optimized will shut down that PSU.
(Corsair and CoolerMaster also have PSU's with 10 connectors. But in terms of quality and warranty they both stays way behind EVGA. Even Seasonic is not the best pick.)

So better split your load to 2 PSU's with a bit of room. If you need for example 900W for 3 GPU's, buy a 1200W or 1300W PSU. The 1300W Gold EVGA PSU's are mostly cheaper than the 1200W xxx PSU's, so the 1300W is the better choice. No need for Platinum and co, if they are only for mining.

Life saver tip: NEVER EVER use cheap 6-pin to 8-pin PCIe adapters to connect just 1 double cable from your PSU to your GPU!!! They will get very hot and if you are unlucky, you can burn down your home!
Another tip: Don't use cheap chinese server/mining PSU's. Protect your investment with quality!

Junction temp is the max of all sensors.  The gpu will start throttling around 110c, so really that is the threshold AMD considers ‘safe’, not 90.  That being said, lower temp = longer lifespan.

I’m uncomfortable w/ 80c, but these guys run hot - without drastically reducing performance, or altering the cards cooling solution, it is what it is.

What miner are you running? Also, are you using Windows OS or some other mining os such as minerstat?

Yes, use 2 of them. Each cable connects one slot from PSU into one slot of your GPU. The remaining 6 pin on that cable just ignore. If you dont have enough cables, just buy some of these cable mods for EVGA PSU's.

If you need more help, just open another thread especially for that problem. Its not really related to hashrate & co  

They dont fit, I'm nearly sure. But in case they will, you have to check the assignment of the pins. You can find that diagrams on their homepages or try to google them.

Nope, I dont have any of these Radeons, only tons of Vegas. Tested one and sent it back after testing.

Different brands, different connectors But some brands are using the same manufacture, like EVGA and SuperFlower for example.

But there are good cable mods on the market. If you don't have enough original cables, just order a few of them. But remember, don't buy the cheap ones. Someday you will regret that decision. Always buy from brands and read carefully the comments on like Amazon. If you see there smoked or burned pictures, skip them!

I have those adapters and one did burn.  I just buy another psu, they are cheap.

Never touch any adapter if you don't want to burn your house down!

1 slot in your PSU for 1 slot in your GPU, if you want to make it correct. So you can fire up 4 GPU's. A 5th card if you use the last 9th PCIe and a good (not cheap!) CPU/PCIe cable.

Many ppl will say "Hey, just use 1 cable for 1 GPU. Get any cheap chinese adapter and its fine."... Never do this! These cables were made cheaply and get very hot and if you are unlucky, it can burn.

Edit: Yes, just connect 1 of these double cables (6+2 and 6) into 1 slot in your GPU, forget the 6 Pin.

DON'T split the remaining 6 Pin with an adapter into 8 Pin and connect the second slot of that same GPU!

Wouldn't four double PCIe cables mean you can connect four GPUs? Then use four of the remaining single ones for GPU 5 and 6?

That PSU as new has 5x single PCIe and 4 double PCIe cables.

Remember to consider your fans power draw when calculating headroom on the PSU.  I think 120mm fans run around .33a on avg - so maybe about 4w each?  If you’re really pushing the limits of the PSU, your best bet is probably an open air rig w/ good spacing, and an external cooling solution if possible.  Here’s my setup for example - the 8x64 rig is on the left.  The spacing alone is generally enough to keep these reasonably cool (40-45c) even at 70-80f/21-27c ambient.  The cabinet is more for noise suppression and dust control (this is my garage/workshop too!) but the airflow helps on those summer days when temps get up significantly higher.  Many people just point a box fan at their rigs. (btw, the fans on the one rig aren’t necessary, but I didn’t bother removing them as I had the power headroom):

Nicehash is okay, if you don't mind pretty high mining fees (5% for payouts less than 0.1BTC to external wallets). The higher fees are partly offset by the fact that their miner always finds the most profitable coin to mine. They had a huge hack two years ago, and they lost lots of bitcoin, and many (including me) lost some of my mining profits. However they've been slowly paying back miners for the lost money. The fact that they've been around for a while, and that they try to pay miners back and do the right thing is why I still trust them. It's an okay way to acquire Bitcoin.

For lesser fees, I use Nanopool for Ethereum mining, and over the years I've had zero problems with them. You can then use an exchange with much lower fees to convert your mined Eth to Bitcoin. I like their clean interface, and you can see one of my miners (2x 1060, 2x R-VII) mining currently there: https://eth.nanopool.org/account/0xa63ffc523e284bfb4a09b46ed2336afe824c57eb

I wouldn't run 4x Radeon VII's in the bedroom unless you have earplugs, or are a very deep sleeper. Also, do you need to cool down your house with air conditioning units? Depending on the climate you live in, AC units can use heaps of electricity trying to cool down mining rigs, and that's why lots of miners choose to run them outside, in the garage or at the patio, for example. Unless you have free electricity, or live in a cold area where you want to warm up your house by mining, I wouldn't run them inside.

Depends on what GPU you are using, and what coin you intend to mine. As an example, a GTX 1060 can consume up to 120 W. A Radeon VII can consume up to 300 W. For Ethereum, if you tune it properly, you can usually cut 25%+ off the power usage, but you don't want to use that as a basis, you always want to leave an overhead so you can mine other coins as needed. Also, as a rule of thumb you don't want to use your PSU at more than 80% since it's not efficient that way. So a reasonable expectation is that a 1600W power supply will probably provide about 1200W power efficiently. That will be able to power 4x Radeon VII's (1200W/300W), or 10x GTX 1060's (1200W/120W).

If you have miners inside, noise can be a problem. If it's outside, it's usually not that noticeable.

Mining wattages and efficiency calculations for Ethereum can be found here:
https://docs.google.com/spreadsheets/d/1w6qQtpwzlKRPSx3hYIpTrO1d29SwAIhOV4CNGi3Jk6Y/edit?usp=sharing

Let me know if it needs corrections. Thanks.

Higher end PSUs tend to have a reasonably flat efficiency curve up to 95+% load.  Here's a measurement of the P2 for example:



And a curve for the T2:



Sure, you lose a couple percent from the peak around 33% load, but it's certainly not worth handicapping your capacity as a result.  I run my 1600 P2s close to full cap in certain situations w/ 8 vega 64s on them.

Also, as I mentioned elsewhere, VIIs can do well over 300w.  The TDP rating is stock - not really something miners (or most gamers spending $700 on a GPU) care about.  That being said, even 300w is most likely pretty inefficient for mining on almost any algorithm - 200-250w is probably the target area for decent efficiency on a VII.  I run ethash at 215w for 82MH/s. 

I would say you could easily plan 5 VIIs on a 1600w PSU - possibly even 6 if you're good about power management.  Mining hashrates, as well as power use, are not fixed quantities.  You can tune your performance of any algorithm however it suits you.  Just because everyone else runs ETH @ 90MHs for 260w, doesn't mean it's the only, or even best, option.

Finally, in addition to noise considerations (and they are loud, though not quite as bad as blowers,) you should think about heat management as well. 1600w is basically a space heater - one you'll be running 24/7, I assume.