The PSU is never hot. It is only for the mobo. Its fan makes a faint cool air flow, which can't harm, only help the circulation. Other PSU's are not visible in this pic. They are separate to have room for the cables.

Since my cards are undervolted I forced a constant fan speed at 50%. At that speed the rig is not too noisy. Of course it is not completely silent but I can live with that. As I said outside is very cold and snowy, so the moist from outside compensates the dry air from the fans. When the temps get normal - about and above 0 C,  I will move my rigs in one room. They are on specially designed tables with wheels (which have breaks to be stable) so I can move them easily around My only concern is the summer... Even in one room with AC they generate heat above 35 C so that a second AC in the next room is not capable of stopping the hot air.

I think both are nearly the same. It depends how much undervolting can take each algorithm. For me zcash is by a tiny bit less power consuming.
Currently here is a winter with -20 C outside. Inside it is +25 C because I have rigs in each room  . Excellent solution for heating the appartment  . But for the summer it is a hell. Two AC 1200 are not enough. I will need a third AC or have to figure out some way of channelling  the heat outside.

On Saturday night, December 7, the value of bitcoin on world markets continued the decline which begun on Thursday, falling to nearly $ 820. Last the cryptocurrency traded at these levels on 22 December. There are several reasons but one of them is a quite important precedent in crypto world. I am talking of an outright attempt of the PBOC (People's Bank of China) to hammer the bitcoin with the hope to stop the devaluation of the yuan.

Recall before it became known about the meetings that had PBOC with the representatives of the three leading bitcoin exchanges in China - BTCC, OKCoin and Huobi. According to its results, the regulator said that due to the high volatility of Bitcoin institutional and individual investors, we need a rational approach to the issue of investment funds in cryptocurrency.

Representatives of the exchanges themselves have tried to reassure the community, saying that we are not talking about any "ban" of Bitcoin in China. However, there are new messages on Saturday night that the PBOC intends to limit the possibility of exchanges in regard to attracting new users.

In particular, according to the publication in Caixin, the central bank intends to prohibit exchanges to mention in its promotional materials yuan's devaluation and the attractiveness of Bitcoin as an alternative investment vehicle, and promote their offline services.

It is also alleged that some of these exchanges were forced to take them to put forward demands and withdrew their marketing strategies.

BTCC posted this notice on their site:

"BTCC regularly meets with the People's Bank of China and we work closely with them to ensure that we are operating in accordance with the laws and regulations of China. As the longest running exchange in the world, we have always adhered to strict AML/KYC policies and continue to be compliant with all current regulations in China. The press release put forth from the PBOC today outlines that there is significant volatility in bitcoin trading, and also quoted from a notice released in 2013 saying that bitcoin is a virtual good and doesn’t have legal tender status. All of our users should be aware of the current policies on virtual goods as well as the risks involved in trading in volatile markets."

Now, what is the truth behind all this veiled explanations? What did really happen? The truth is as simple as that: the owners of BTCC, OKCoin and Huobi selled enourmous amount of bitcoin for yuan to satisfy the dictatorship of PBOC. This lead to an avalanche type of effect on the price of bictoin. I found it particular disturbing that the idea of decentralized cryptocoin is compromised by the owners of the biggest exchanges. Let's protect our freedom and fight back! Get out of any chinese exchanges, sell yuans and buy cryptocoins. Let's show we are stronger!

For all my cards I get 4% improvement. I got it for undervolted and overlocked 390 with -a 1, and 280x with -a 1 or -a 2 depending on the model. For example XFX are better with -a 2 (215 sols vs 210 with -a 1), while Saphire Tri x is way better with -a 1, where I get 230 sols on stock cards vs 218 with -a 2.

Do you want me to sent mine faulty risers to prove your theory is far from the reality?

I've been mining for nearly a year. Of course I know about this page. Obviously you didn't have risers that work with their own will like mine did. Again: bad riser can cause the OS not to see the card in the Device manager, or you can see it randomly on restarts, or can work really poorly crashing the drivers at the end. This can't be checked with this page or any other methods except changing the risers. Believe me, I had 5-6 faulty risers (powered usb) ordered by ebay. Finally I ordered more expensive but really good risers from amazon and they do their job perfectly.

You should change your risers first of all. I had bad luck with shitty risers months ago. Sometimes the card appear sometimes not. I thought the problems were elsewere but after changing two (!) packs of risers finally the problems dissapeared for good. The next thing is to use windows 8.1 64 bit, especialli if you have h81 mobo. They are really well optimised for this OS. Moreover, windows 10 will have bigger load on the cpu which can slow your cards when mining. In my case win 10 is above 90% whereas win 8.1 around 20%.

You should see 6 cards after the drivers install and 1 probably with an exclamation mark in the device manager. You need to run the 6 card mod to be able to mine with all 6.

810 h/s on stock clock and memory R9 390, undervolted -150mv

Claymore, please add the option -r 1 from the other miners to close the miner and execute reboot.bat.  Currently -r 1 restarts the miner after 1 min. Sometimes one of my cards hangs, causing the miner to freeze even with the options -w 1 or/and -r 0. Also it is better to show not the thread than hangs (in my case 8 and 9) but the card (I guess it is card 4).

Yesterday I moved my rigs to dwarfpool. For the last 24 hours I got at least 15% more ZEC than flypool. I don't trust in general the hashrate statistics, but in flypool it was always 10% less than the miner hashrate. Dwarf always shows 5% above the miner. Also the rejected shares in dwarf are 0.13%, whereas in flypool they were around 0.55%.

You are comparing stock voltage 390 with undervolted 480. Mine 390 are undervolted -100 to -150 with the stock clock and memory (they work for weeks without crashes but the exact undervolting depends on the model; I use Trixx utility). They consume 200-210 W from the wall measured by watmeter. The whole rig with 6 390's consumes 1300 W at the peaks.

You can use the calculator http://www.whattomine.com/ both for GPU mining and ASIC minig with Antminer S7 (for BTC and other "Asic friendly" coins).

The real price for 390 cards is around 250$. Don't look at the old amazon offers which are ridiculously high. However I warn you (and everyone planning to invest in new rigs) that most probably by the time of arriving of the cards, the profit will drop so much that the ROI will be impossible in near future. Look at the plummeting prices of ETH and ETC curently. The pressure on ZEC and XMR is too high now, so they will not hold the current price for long.

With a stock XFX 280x I get 471 h/s. With a Sapphire tri-x 280x I get 490 h/s. It corresponds to the calculator, but still... Judging from the lower power consumption compared to other Claymore miners, I feel that there is a room for 10-15% optimisation. I didn't try wolf miner but according to http://monerobechmarks.byethost5.com/ the speeds for both miners are (may be) similar. At least for 390 and 480 series, because for 280's the info is scarce.

Ко рече, ко?

Some noobs are trying to hijack the tread for the Claymore miner, which is AMD only! Please go find another forum! Btw, you are jelous because you came too late for the ZEC party   Actually you will always be, because of the Nvidia stupid politics. You will fool nobody here. You forgot the past month and a half moaning in numerous posts here for a Nvidia miner

Dang it! Same here  

None of these statements is true. For 2) check your Bios. Every Bios has an option to turn on the computer after the power is restored, including windows machine. Of course you have to put a shortcut to the miner in the start up menu.

ZEC full reward coming in 3 hours.  
http://cryptomining-blog.com/8378-less-than-100-blocks-remain-until-the-end-of-the-zec-slow-start-mining/