Topic: First power bill for my 6 GH/s rig (Read 10105 times)

I don't think I laugthed so hard in a long time... and not those fake LOL... but a real LOL that lasted almost a minute

I am in.
Specify what kind of pictures will satisfy you as "photo proof"?

lol

now I REALLY dont believe you!
I will pay 20 BTC bounty if you take pictures of 6 5970s mining in that dog house.

Listen, I give up. Is that what you wanted to hear? Good for you, you win. Yay. Now please drop it because this is beyond a joke. I'll keep cooling how I want to, and you can keep cooling how you want to.

Mods, could the offtopic be split off? OP, sorry for ruining your thread.

The claim dispute may or may not involve aftermarket heat-sinks (which are availible for under $100 btw, your shopping skills suck), as the post didn't specify.  Also, the claim in dispute included an additional fan for every rig.  In addition, there was this little gem which you completely ignore-


So okay.  Assuming he doesn't have the custom heat sinks is already a stretch in your favor.  But given that, you honestly don't think the addition of an extra fan per rig AND an evap cooler would be enough to compensate for lack of said heat sinks?

A quick google on evaporative coolers provided this bit-


While I am sure 30 degrees is a bit of an extreme case, I don't think it would be too crazy to assume that an evap cooler could lower the incoming air by 10-15F, which would more than make up for the difference accounted by those oh so expensive heatsinks.

Calling it a lose is wishful thinking, or a desperate act of someone who knows he was proven wrong

Okay, I don't care to get sucked back into this, but in the interest of extending an olive branch...


Ambient doesn't ever hit 80C under my scenario.  It peaks at "real" ambient plus 6.5F (3.6C).  So you have no worries about your PSU or VRMs or CPU or NB or SB or anything except the GPU cores themselves.  I don't point this out defensively, but as a positive, because...



Aside from the fact that I never claimed 110F (okay, a bit defensive), you can read my numbers on a more positive note relevant to your project.  I didn't prove it as "impossible", but rather, a function of the GPU cooling device itself.  Your idea of using a water cooler should nicely get around that limitation, easily buying you another 15-20C with which to play.  That puts you solidly in the feasibility range up to an ambient of 134.5F

Again, though, you make a good point about cost.  It still makes more sense to me to just throttle your mining rigs down over a certain temperature, than to go for a complex, expensive per-GPU cooling solution.

I call it lose.  The claim being disputed didn't involve aftermarket heatsinks.  Especially not .... $140 aftermarket heatsinks.

20KW of 6990 @ 1KW per quad 6990 system = 80 GPUs.  $140 aftermarket heat sink * 80 = $11,200 in heatsinks.  

So using $11,200 in aftermarket coolers one could keep the cards at not so comfortable 90C.  Using stock heat sinks temps would be beyond the hard thermal throttle limit.  That at least sounds plausible.  Nobody said cooling was impossible under any circumstances.  The claim made earlier in the thread was bogus and you just proved it.  Even with 10 grand in cooling gear the cards will be extremely hot.  Mining at 90C isn't going to produce stable efficient rigs.  You also need to account for the fact that PSU efficiency declines rapidly when ambient is >80F which is going to add extra load, wasted energy, and even more heat.  

Still interesting analysis.  BTW I am building a watercooled server rack to cool 20GH/s without airconditioning in 100F temps.  Obviously I don't think it is "impossible" but you have demonstrated the claim made by up thread is impossible.  Thanks.

Okay, sick of this discussion, so I did the math.  Go ahead and carry on arguing with it, without me.

Repeating my earlier point, the average bedroom measures a mere 86ft^2, or roughly 600ft^3, Meaning a 2400CFM box fan will completely remove the air from the room every 15 seconds.  Two will then do the job every 7.5 seconds.

1 BTU will heat 55 ft^3 of air (at STP and H) by 1F.  20KW = 68290BTU/hr.

20KW will therefore heat 3755950 ft^3 per hour, or 62600 ft^3 per minute, or 7825 ft^3 per 7.5 seconds, by a single Fahrenheit degree.  Or, put more usefully, it will heat 600ft^3 by 13F every 7.5 seconds;  At 4800CFM (one full air-exchange per 7.5 seconds), that gives us a mean-over-time rise of 6.5F - Pretty damned close to my "feels 5F warmer" estimate from the woodstove.  Funny, that.

For the rest of this, I will refer to the Radeon 6990, the hottest single card (AFAIK) in common use.  Your "preferences" of running cooler than spec aside, a Radeon HD 6970 (and the 6990 just contains two downclocked 6970 Cayman chips) has a tMax of 194F.

Now we have an interesting result here - With the stock cooler and under full load, a 6990 will violate its own spec at ANY ambient over 73F.  This would make the naysayers appear correct...

But!  We've also demonstrated that two box fans will clear 20KW of heat from a room, with a 6.5F steady-state rise.  That reduces the problem to airflow at the ambient/heatsink interface.

Since we've limited this discussion to airflow, I'll limit the following to fan/heatsink combos only.  Using a halfway decent aftermarket cooler, you can drop the under-load temperature to below 160F (you can find similar numbers in dozens of articles on Tom's Hardware or AnandTech, if you like - For my exact source, I found http://www.kitguru.net/components/graphic-cards/zardon/arctic-cooling-accelero-twin-turbo-6990-cooler-review/5/ helpful in that it described the test conditions sufficiently well to extrapolate from them), for a plausible under-load delta-T of a mere 87F.

This, then, gives us a "feasibility" result of 107F at the intake, or a raw outside temperature of 100.5F.

Call that a win or a lose, as you like.  Where I live (if I didn't pay a fortune for electricity), it would put me over my "thermal budget" for two days in the past decade (no, DeathAndTaxes, not talking about winter, nor did I ever).  And I don't live in Sweden.   

Okay, I just went to my backyard, negotiated with my neighbor's dog, he was kind enough letting me put the fan back in, along with fake LEDs, and took a picture -- but it looks beautiful, doesn't it? 

Negative. I was just an onlooker before decided to post the picture. Although I was a proponent of "open air operations" in a similar thread last May: 
   https://bitcointalksearch.org/topic/m.141748

That being said, do you really want to pay 5BTC to see 3 boxes sitting in a dog house? I can tell you they fit perfectly.
 http://www.amazon.com/gp/product/B000QJETYS/ref=oh_o04_s00_i00_details

my god

did you really just go out in your back yard and put a box fan in your neighbors dog house to win an argument on line?

I will pay 5 BTC bounty for photo proof there is six 5970s mining inside there.

I have to see it.

No way! Tilapia require a permit there? Hit up chinatown and grab some live tilapia or catfish. No one will hassle you about permits there, and I am positive you can get both in Los Angeles. The only trouble is going to be finding females if you want to breed them.

I want to grow tilapia but they require a license here in California.  I think it's cool you actually did a cannabis aquaponics system tho!

You should paint the roof of that dog house white to better reflect the sun. Better yet: Cover it with aluminum foil

Epic! ^_^

lol. Depending on seasons and time of the day, I can change from bitcold to bithell.

So your name is a lie then?

Those bits aren't cool.  More like bithot.