How much of a temperature gradient is required?

[yochdog]

Hey all,

For you experienced farm operators, I have a pretty simple question:

How low do you keep the ambient temperature in order to feel comfortable that your farm will run smoothly?  I suppose it is OK to allow the ambient to be 90-100 degrees even, as that is still considerably less than a GPU running at 80 Celcius (about 175 F).  I don't think this is ideal, as the fans would have to be screaming, but theoretically it would still cool the GPU.

Can you guys add some thoughts on this?  What is optimal in your mind in terms of striking a balance between efficient cooling, and just throwing money away on excess AC?

[1714054667]

1714054667

[DeathAndTaxes]

I found that 80F-86F was fine for my setup.  I set the AC to 86F.  I know even some data centers are going to warmer temps to improve efficiency.  I think Google runs one of their datacenters with ambient in mid 80s.   Beyond 90F I would start to see random lockups and crashes.  Once when AC breaker tripped the garage hit 100F and it was "dead rig city".  I wouldn't try to push it that far unless you want a full time job rebooting rigs.

Obviously it is going to be very system dependent. The higher the ambient temp the more airflow you need to keep GPU core at the same temp.  If you got some serious fans you likely can get away with low 90s.  With enough airflow you can keep any component at delta to ambient.  Technically yes that means even with 100F (37C) ambient temps you could keep a GPU core <40C.  You likely would need some monster 300W turbine fan but it could be done.  Probably not smart or economical so it becomes balancing the cost in airflow vs cost to lower ambient temp.

Now that my farm is watercooled the radiator is outside in 100F temps and a single fan keeps the core's <50C.   The garage is usually 90F+ due thermal energy from PSU and other components but they don't see to mind the heat.

[rjk]

D&T, could you post updated pics in your thread?

Yochdog, I would tend to agree with what D&T has said - above 95-100 you will have issues, but 85ish shouldn't hurt. Now if it was 100+ and you had some high velocity fans moving a LOT of air, you might not have issues.

[DeathAndTaxes]

D&T, could you post updated pics in your thread?

Yeah maybe.  I am working on other stuff right now and the farm is pretty much self managing at this point.  I have gotten so lazy I just power cycle all the rigs once a day to catch any crashed cards (rare).  I hadn't thought about it until yochdog.  The days or tweaking, monitoring, and tracking are done.  Just going to let those cards hash into the sunset until the inevitable difficulty rise renders them obsolete.

The stuff I am working on now is much more exciting.

[yochdog]

Thanks for this.....it is helpful.  I am shooting for 80-85. 

[TheHarbinger]

Ambient temp only matters if your cards are overheating with their fans running at 100% and decent airflow over them. 

My rigs are set up in a back bedroom next to the windows with a box fan pulling air across the cards and exhausting it outside.  Living in central Florida this time of year, ambient in that room exceeds 90F routinely during the day until the rain hits.

Even during the peak of the days heat, my fans don't exceed 70%, and GPU temp never exceeds 75C.

I will never use the A/C in that room, the two box fans eat up about 1A, the A/C eats up about 7A.

[yochdog]

Ambient temp only matters if your cards are overheating with their fans running at 100% and decent airflow over them. 

My rigs are set up in a back bedroom next to the windows with a box fan pulling air across the cards and exhausting it outside.  Living in central Florida this time of year, ambient in that room exceeds 90F routinely during the day until the rain hits.

Even during the peak of the days heat, my fans don't exceed 70%, and GPU temp never exceeds 75C.

I will never use the A/C in that room, the two box fans eat up about 1A, the A/C eats up about 7A.

This is great to hear.  Off to home depot after work.  Box fans for 15 bucks! 

[rjk]

This is great to hear.  Off to home depot after work.  Box fans for 15 bucks! 

lol, it must be great to have cheap power. Don't those things use like 200 watts each?

[TheHarbinger]

This is great to hear.  Off to home depot after work.  Box fans for 15 bucks! 

lol, it must be great to have cheap power. Don't those things use like 200 watts each?

Kill-A-Watt says 1.14A with 2 of them running on low.  That is for sure a hell of a lot less then running the window shaker A/C in that room would be. 

And no, my power isn't "cheap"  $0.12 kW/h

I got 6 of them from SEARS for $3 each.  Pretty sure the price was wrong in the computer.  I only walked up to the register with one, when the price came up, I went back and got all the rest they had.

[yochdog]

This is great to hear.  Off to home depot after work.  Box fans for 15 bucks! 

lol, it must be great to have cheap power. Don't those things use like 200 watts each?

I have no clue.....but that seems really high.....

[rjk]

This is great to hear.  Off to home depot after work.  Box fans for 15 bucks! 

lol, it must be great to have cheap power. Don't those things use like 200 watts each?

I have no clue.....but that seems really high.....

Could be that I'm victim of faulty info. Should be able to check the label though. 1.14A for 2x on low means 68 watts or so each, so that sounds a lot better.

[zvs]

my industrial fan that's blasting air in from the window consumes 150 watts.  all other area on the bottom of the window is sealed.  top is open about 3 inches,  and passed the paper test

ambient temperature in that room easily hits 95o during the day.   if you wanted to count heat index, it'd be over 100


each computer has its own table top fan which draw about 40 or 50 watts each (and open case)

[Graet]

hmm well, over summer (I am in Australia so its winter now) I moved my mining rigs outside to the back verandah, we had a week of 40Deg C + days, rigs ran fine at under 80Deg C using cgminer, some undervolting and some gpu management, my target temp is 75Deg C.

The guy that develops cgminer is also in AU and spent some time tweaking cgminer before our summer, he realised in our summer heat would be an issue, so the work was done ages ago- enjoy

actually it saved me money on power as well as not needing to use extra power to cool cards (fans a/c etc)

Now its winter the rigs are back inside and its lovely

[ssateneth]

For me, ambient is whatever the temperature is outside Outside mining rigs ftw! Free air conditioning.