Rule of thumb would be 220 cfm for each antminer and maybe about that much more for the GPU rug.  That might get you into the neighborhood of 3000 CFM for your setup.

If you have a LOT of natural ventilation / open windows etc. you may be able to get away without a lot if forced make-up air, but to be safe you'd want enough air being forced into the basement to replace the hot air your forcing out.

A cheap answer to getting ~ 3000cfm might be something like this:
http://www.globalindustrial.com/p/hvac/fans/blower/portable-ventilation-fan-12-inch-with-16-feet-flexible-ducting

You can order a 12" exhaust that looks similar to an oversize dryer vent through Home Depot to cap off the outside, or you can just shove the exhaust hose through a window if you have access.

My guess is with the crash this week a lot of those greedy buyers from this weeks batch decided to not follow through with their orders.

I picked up a couple D3's, but we'll see if there even profitable by the time they come in.  I'm hoping to maintain $20 - $25 daily by November, but everyone's just guessing at this point.

Fully agree with Marthor's comments.   You may laugh it as the 'point and click miner' or whatever, but the automatic switching and the simplicity of payment seems to make it a pretty good value for me.   Ive been using them with a very small number of cards for about 18 months and when Ive experimented with direct mining its generally paid less.

In the long run, the more 220 circuits you can start using the better off you'll be.

220 x 20A = 4400watts.  de-rated to 80% for 100% duty cycle = 3520 continuous watts of load on a single circuit.  

2 D3's and an L3+ would put you at about 3200 watts.




on the 120 / 15A route,  1440 watts per circuit max, so one miner per circuit no matter what.

....  That's code for "Go look in the Altcoin mining section"


Bitcoin mining does not use video cards.

.... And Out of stock....


Missed it by that much!
(Yes that was a Maxwell Smart reference)

At the end of the purchase process, before it provides a payment address it asks a captcha style question.  i.e. 39 - 2 but the two is in a picture.      I answer teh question then it just sits there waiting to verify.  no busy animation, refresh, activity - nothin!


The miner is $2300 (higher than last time) and would ROI in a few months if difficulty wasnt about to skyrocket.   I think it'll still be ok though in the long run, esp with $70 LTC.

Chrome (like most of the internet)     

G/L... Im going to hang out for another 5 minutes or so.. took too much work to get this far!

Trying to get a couple L3s tonight.  fought through to get them in my cart and at the confirmation screen.   When answering the little math question at the end it sits on "Verifying! Please do not repeat the submission"

Do I sit here all night, or do I eventually give up and try to resubmit?   I tried this the other night with D3's and never got my order through (to the math screen 3 times).


Thanks for any tips from you pros!

Escrow? 

Payment methods?   How much inventory do you have available?

thanks

When you complete your order, Bitmain will tell you exactly how much BTC to send - including S&H. 

You have about an hour to complete the BTC transfer for that exact amount to retain your order.

If you have any customs charges to pay, they will come later either directly to your customs authority or through your shipping co.

If you don't want an S9, its about the best deal you can get (unless you know another good option?)

If youre just mining with a couple of units, you should be fine behind a normal SOHO grade router / firewall.   Be careful not to open up any weird ports coming in on the router (Port forwarding, virtual server etc.).  The less doors that are open, the less likely it will be for a hacker to fund their way into your network.

If you've secured your internet connection, the next easiest way for an attacker to get to your miners would be to compromise one of your laptops / desktops / phones that have access to the same network and use them to access your miners.   An easy way to avoid this would be to separate your mining network from your home network.  You can add a second router 'down stream' from your first one and use it to connect your mining equipment.  This second network would treat your house network as if it were the internet (WAN) and would keep most access / ports closed (you could even disable wifi if you want since it wont be needed).   This will limit your ability to manage the miners from devices in your house that aren't part of that mining network.  Keeping an old laptop or desktop isolated with the miners would be an option to make that a bit easier.


Security is always a trade off with convenience.

If you had a constant / steady draw of water usage in the house, yes you could theoretically do this.

The heater core would need to have a constant fresh supply of water moving through it, and would not be pulling out that much of the heat from the miners so you still have a need to circulate air. In reality, its probably not worth the hassle or risk of leaky pipes near your miners.

Probably best to post this in the marketplace.  Would also suggest offering escrow.

I used PayBis last week and it worked fine.   Paid a premium of course, and they do require verification.

My CC company initially declined the purchase as fraud, but provided an SMS prompt to allow me to verify the transaction, after that it went through no problem.

Coinbase's vault uses a double authorization to move funds.   You have your two 'managers' email addresses registered on the account so that it requires both of them to OK any movement from the vault to other transactional accounts.

Im sure there are other ways, but that one is alive right now...

Your video card is whats impacting your profitability, not your network.   A 640 probably isnt going to be profitable for much of anything out there.   If you use NiceHash as an example, the lowest comparable card I see on their list is a 650 TI (more powerful than your card) and it currently makes 17 cents a day, before you pay 25 - 50 cents to run your PC all day.

Your not dunking the miners in water, they're just in moist air.   No issue with rusting.   Even if it did, the miners would be worthless due to difficulty way before the aluminum eroded any significant level.

Might check this thread  I started a couple days ago on the same topic.   seems the consensus is you're ok.

https://bitcointalk.org/index.php?topic=2055982.0