The AMD Crimson Relive drivers should support both cards on Windows. I have a Pitcarin card in my rig together with RX 480's and I was getting similar reduced hashing outputs. What I did was connect the primary 16x PCI-E slot to the Pitacarin card's 1x riser and use that card with the monitor dummy plug. I then uninstalled the drivers in safe mode using DDU and reinstalled the latest 17.5.2 drivers. All the cards are working normal now.

Also I've found that the Claymore miner sometimes can change the order the cards are detected, so you need to make sure the right settings are applied to each card. e.g. my Pitcarin card will only take 1500 MHz for the memory clock at intensity 4, while the RX 480's can take 2100 MHz at intensity 7.

You need to plugin a display or dummy plug in to the VGA connected to the primary 16x PCI-E slot for the AMD drivers to be able to read the temperature and fan speeds, so they can be set with the miner. You also need to set the primary video to the PCI-E slot in the motherboard bios and not the onboard video.

What I meant is the changes made by the pixel patcher are not permanent. You have to run the pixel patcher every time you install the AMD drivers so it can bypass the signature check.

No guarantees. I also just bought another RX 480 from Amazon that was sold by Amazon as new. The card they shipped had obviously been repackaged and the serial number didn't even match the label on the box. I decided to give it a try, since they are no longer available anywhere. I had to return the card after no matter what I did, the card would not mine for more than 2 minutes before crashing.

In any case, all the pixel patcher does is change some registry entries made by the driver, so it will bypass the signature check with a modded bios. If it doesn't work, you can just reinstall the drivers.

I have the same cards and they came with Samsung memory. You can verify the memory brand of your card in GPU-Z.  It's pretty simple to modify the memory straps of your original bios. All you need is atiflash and Polaris Bios Editor:

https://www.techpowerup.com/download/ati-atiflash/

https://github.com/caa82437/PolarisBiosEditor

Extract the Atiflash zip to a folder on your Desktop and open a command prompt in that folder. The first step is to backup your original bios in case something goes bad. At the command prompt type:


The above command assumes the index of video card you want to backup is 0. It's best to flash the cards one at a time and remove any other cards so you won't make a mistake. After you backup the bios, extract the Polaris bios editor zip to another folder on your Desktop and copy the bios you backed up to that folder. Run Polaris bios editor and open the bios in it. On the bottom right box, you will see the memory timing values. Most people start with copying the value in the 1500 or 1625 MHz box and replacing all the higher frequency values so they are the same. What works best is highly dependent on the type of card you have and the type of memory it uses, so you will have to research what works best for the cards you have. On my Asus STRIX RX 480 GAMING 8GB OC editions, they came with Samsung memory and the 1750 strap over the 2000 works best.

Once you adjust the memory straps save the bios and copy it to the atiflash folder. Flash the bios to your card with:


After it finishes loading the bios, don't reboot as it asks you to. Since you are using a modified custom bios and the new AMD drivers since 16.12 check for a valid bios signature, you need to patch the driver or use a driver older than 16.12 for Windows to recognize the card. To patch the driver download atikmdag-patcher:

https://www.monitortests.com/forum/Thread-AMD-ATI-Pixel-Clock-Patcher

and use it to patch the driver before rebooting.

BBT also posted the bios he used in the description of the YouTube video where he shows how to setup the Asus RX 480 rig he built

https://www.youtube.com/watch?v=3C1dr-HDDYs

I have the same cards, OC edition. I assume you have a modded bios. All you should need to do is use the pixel patcher after installing the drivers to bypass the signature check and reboot.

https://www.monitortests.com/forum/Thread-AMD-ATI-Pixel-Clock-Patcher

Skein is a POW mining algorithm used by a couple coins like Skeincoin, Digibyte and Myriadcoin

http://cryptomining-blog.com/tag/skein/

It depends on the GPU's and if you plan on dual mining. I recently did a build of the BBT mining case below out of two 8ft pieces of 1/8" x 3/4" angled aluminum, one 8ft 1" x 2" piece of pine and #8 1/2" self-tapping screws. The case will fit up to 7 RX 4XX/5XX if you put them about 1 inch apart. For 8 GPU's I would increase the length of the longest frame section by 4 inches from 19.2 to 24 inches and I would also increase the frame height by 2 inches from 9.25 to 11.25 inches, which means you will need to use three 8ft pieces of 1/8" x 3/4" angled aluminum instead of two.

https://www.youtube.com/watch?v=D5xNrlxsCVs

The only tools needed were a drill with a 3/32" hex titanium drill bit to drill pilot holes and a #2 phillips screwdriver bit. A hacksaw with a 32 tooth blade and a plastic miter box to cut the aluminum and wood. It took about 4-5 hours since it was my first time building one. The case is very sturdy and can support up to 7 GPU's. You could also use wood or 1/16" angled aluminum pieces if you want to save money. Way cheaper and quicker than ordering a case online.

Bump!

If you can try the card in another machine.

Your miner settings could be too high. Try backing off the GPU core 10 MHz and the Memory clock 50 MHz, or lowering the intensity. Also check the cables and connectors on the card.

Sounds like the driver is crashing I would uninstall the driver in safe mode using DDU and then reinstall the drivers. You also don't need cuda for AMD cards so uninstall that as well.

I don't know if it will solve it but I recently upgraded to a dual power supply setup which had me researching on how to connect them safely.

I came across posts suggesting powering the riser and PCI-E power connector on the card with the same PSU. Others say the psu that powers the motherboard must also power alll the risers. The slave psu should only power the PCI-E power connector on the card.

https://bitcointalk.org/index.php?topic=1761303.msg17825999#msg17825999

https://bitcointalk.org/index.php?topic=1843586.msg18351224#msg18351224

Ultimately, I did follow the latter suggestion as it seems logical the same power supply that powers the motherboard should also power the risers connected to the PCI-E slots on the motherboard. The second slave power supply only powers the 6 & 8 pin auxiliary power connector on the video cards. According to another post I came across that connecting the PSU's that way ensures they share the same ground, which is important.



https://bitcointalk.org/index.php?topic=443540.msg4878774#msg4878774

Some cheaper PSU's also use the 5V rail to regulate power, so you could try plugging in a 5V case fan directly to second PSU or test the ATX connector pins with a multimeter.

Is the 4/8 pin cpu power connector from the primary PSU plugged in the motherboard?

The ROI on a single 1080 TI at $650 each is 3 months running 24/7 with no downtime.

https://www.coinwarz.com/calculators/zcash-mining-calculator/?h=700&p=250&pc=0.10&pf=0.00&d=2351899.59031740&r=10.00176152&er=0.09557888&btcer=2594.03120000&hc=650

The $190 PNY GeForce GTX 1060 3GB Graphics Cards can do 23.5mh ETH and 268 SOL/s ZEC each @ ~60W per card.

https://www.youtube.com/watch?v=1uhSfOpvHks&feature=youtu.be&t=7295

The ROI on the card for Zcash is less than 2 months currently. Tough to beat if you can get it for less than $200.

https://www.coinwarz.com/calculators/zcash-mining-calculator/?h=265&p=60&pc=0.10&pf=0.00&d=1941897.72385156&r=10.00064000&er=0.09776000&btcer=2586.01160000&hc=0.00

The $190 PNY GeForce GTX 1060 3GB Graphics Cards can do 23.5mh ETH and 268 SOL/s ZEC each @ ~60W per card.

https://www.youtube.com/watch?v=1uhSfOpvHks&feature=youtu.be&t=7295

THE ROI on the card for Zcash is less than 2 months currently. Tough to beat if you can get it for less than $200.

https://www.coinwarz.com/calculators/zcash-mining-calculator/?h=265&p=60&pc=0.10&pf=0.00&d=1941897.72385156&r=10.00064000&er=0.09776000&btcer=2586.01160000&hc=0.00

You are going to need system RAM, a good brand of 2133 MHz DDR4 4GB is enough, check the motherboard website for module compatibility. No point in going with a more expensive SSD, a basic 64GB is enough. SLI or Crossfire is not used for mining. Otherwise looks good.

No point in waiting for the 8 GB. The hashrate is almost the same after BIOS mod. I say get the 4GB. Cheaper, so ROI is quicker and the faster you start, the faster that will happen.

Don't worry about it. The Dag ~0.73x per year growth level puts it at 4 GB some time in 2019. By then the cards will have payed off many times over or ETH will move to POS. You can always resell the cards to recover a good part of your cost too.

https://github.com/ethereum/wiki/wiki/Ethash-Design-Rationale

That's correct. The hashrate is per card. The miner software divides the hashing work load among all the cards connected to it and then sends the shares to the pool and you can see an estimate of the total hashrate which is also reported in the miner.