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Dual 7990 litecoin mining

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Posted · Original PosterOP

Hello once again guys,

 

so I am currently mining litecoins with a single 7990 in my fractal design define XL R2 (with the sidepanel open), fans at 45% temps stable at 87 and 80C on gpu1 and 2.

I was planning to upgrade to two 7990s once haswell-e comes out anyways but I am also planning to watercool my build by then.

 

So 7990s are no longer being made and hardly in stock as is, if they are completely gone by the time haswell-e is out I'll get two 280x's and run that in quadfire.

However I got my eye on a new 7990 that is dropping in price rapidly I am considering buying it with some of the money I got from mining with the single 7990, but heat issues.

 

I tried mimicing the airflow restrictions by stacking a few things to the height the second 7990 would be at and in order to run it at 95C I had to turn the fans up to 70% (which is pretty loud)

I am assuming it will run 5-10C hotter than that when there is an actual 7990 underneath it and not dummies. I can live with running the cards at 95C they are made for a max of 120 and constant cycling of temps is what damages cards in the long run not just how hot they get, I can live with turning the fans up to 60%.

 

My question to you is if I end up buying the second 7990, what can I do to lower temps?

Take it out of the case and put the motherboard on a horizontal surface so it has better airflow for the gpus?

I cool my cpu with an H220 so I can have that blow cool air directly at the gpus if I take it out of the case.

 

What other options do I have?

Does someone with more experience know if it's possible to remove the automatic shutdown of windows once the gpus hit 100C, does it matter if the GPUs run at 110-115C constantly instead of 90C?

What other cooling options do I have other than aftermarket cooler/watercooling?

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http://www.tomshardware.com/reviews/radeon-hd-7990-crossfire-overheat,3539-2.html

 

IF you run those gpu's as hot as you say you want to,

 

1. They're going to throttle like mad

 

2. You'll probably kill them very fast

 

3. You'll probably get half the khash/s that you should because of the throttling


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Posted · Original PosterOP

I should note I have my 7990 underclocked to 900 Mhz core and 750Mhz memory, undervolted to 1000 mV.

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put some more fans on the gpus or go watercooling 


If you tell a big enough lie and tell it frequently enough it will be believed.

-Adolf Hitler 

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Are far apart will they be?


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Posted · Original PosterOP

http://www.tomshardware.com/reviews/radeon-hd-7990-crossfire-overheat,3539-2.html

 

IF you run those gpu's as hot as you say you want to,

 

1. They're going to throttle like mad

 

2. You'll probably kill them very fast

 

3. You'll probably get half the khash/s that you should because of the throttling

 

1. will it be noticable for mining tho, mining is different from gaming and with the single 7990 all I had was crashing because of the heat no throttling at all.

 

2. Or not, a lot of temperature changes (hot cold hot cold) will lower the life (because of expanding/shrinking of the components), a card that is rated at 120C will not die any faster when it's running at 100C compared to 50C if I understand things correctly.

 

3. Fair point.

 

put some more fans on the gpus or go watercooling 

 

How do you mean? Get an office fan and point it at the open case  :P

I have the radiator mounted in the front as intake blowing cool air to the gpus.

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Jesus, a pair of 7990's.

 

What kind of power are you consuming with those beasts?


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Posted · Original PosterOP

Jesus, a pair of 7990's.

 

What kind of power are you consuming with those beasts?

 

should be around 800W max, which comes down to 1 euro and 50 cents a day.

So about 500 euros a year, but I am not planning to mine after 2014 because difficulty.

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1. will it be noticable for mining tho, mining is different from gaming and with the single 7990 all I had was crashing because of the heat no throttling at all.

 

2. Or not, a lot of temperature changes (hot cold hot cold) will lower the life (because of expanding/shrinking of the components), a card that is rated at 120C will not die any faster when it's running at 100C compared to 50C if I understand things correctly.

 

3. Fair point.

 

 

How do you mean? Get an office fan and point it at the open case  :P

I have the radiator mounted in the front as intake blowing cool air to the gpus.

 

If the card was rated at 120 c, why on earth do they throttle at 102c that hard like in the link I posted?  And where did you find that they were rated at 120c? Everything I've found says 7970 chips are rated for 99C max, and last I checked a 7990 is basically 2 7970 gpu's :9


Stuff:  i7 7700k @ (dat nibba succ) | ASRock Z170M OC Formula | G.Skill TridentZ 3600 c16 | EKWB 1080 @ 2100 mhz  |  Acer X34 Predator | R4 | EVGA 1000 P2 | 1080mm Radiator Custom Loop | HD800 + Audio-GD NFB-11 | 850 Evo 1TB | 840 Pro 256GB | 3TB WD Blue | 2TB Barracuda

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With a slot inbetween they should be ok if you put a fan to accommodate the first gpu. Also to my knowledge for a gpu to run hotter is worse than it running at a cooler temp, because the caps are rated at 105 degrees however with the caps running cooler the life expectancy will be longer. And you know no dead gpu's are happy gpu's. 


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Posted · Original PosterOP

If the card was rated at 120 c, why on earth do they throttle at 102c that hard like in the link I posted?  And where did you find that they were rated at 120c? Everything I've found says 7970 chips are rated for 99C max, and last I checked a 7990 is basically 2 7970 gpu's :9

 

http://webcache.googleusercontent.com/search?q=cache:qRTNbKwNKjUJ:www.overclock.net/t/1196856/official-amd-radeon-hd-7950-7970-7990-owners-thread/11120+&cd=1&hl=en&ct=clnk

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Hello once again guys,

 

so I am currently mining litecoins with a single 7990 in my fractal design define XL R2 (with the sidepanel open), fans at 45% temps stable at 87 and 80C on gpu1 and 2.

I was planning to upgrade to two 7990s once haswell-e comes out anyways but I am also planning to watercool my build by then.

 

So 7990s are no longer being made and hardly in stock as is, if they are completely gone by the time haswell-e is out I'll get two 280x's and run that in quadfire.

However I got my eye on a new 7990 that is dropping in price rapidly I am considering buying it with some of the money I got from mining with the single 7990, but heat issues.

 

I tried mimicing the airflow restrictions by stacking a few things to the height the second 7990 would be at and in order to run it at 95C I had to turn the fans up to 70% (which is pretty loud)

I am assuming it will run 5-10C hotter than that when there is an actual 7990 underneath it and not dummies. I can live with running the cards at 95C they are made for a max of 120 and constant cycling of temps is what damages cards in the long run not just how hot they get, I can live with turning the fans up to 60%.

 

My question to you is if I end up buying the second 7990, what can I do to lower temps?

Take it out of the case and put the motherboard on a horizontal surface so it has better airflow for the gpus?

I cool my cpu with an H220 so I can have that blow cool air directly at the gpus if I take it out of the case.

 

What other options do I have?

Does someone with more experience know if it's possible to remove the automatic shutdown of windows once the gpus hit 100C, does it matter if the GPUs run at 110-115C constantly instead of 90C?

What other cooling options do I have other than aftermarket cooler/watercooling?

strap a box fan to the side of your case.


AAAAAAAAAGGGGGGGHHHHH!!!!

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1. will it be noticable for mining tho, mining is different from gaming and with the single 7990 all I had was crashing because of the heat no throttling at all.

 

2. Or not, a lot of temperature changes (hot cold hot cold) will lower the life (because of expanding/shrinking of the components), a card that is rated at 120C will not die any faster when it's running at 100C compared to 50C if I understand things correctly.

 

3. Fair point.

 

 

How do you mean? Get an office fan and point it at the open case  :P

I have the radiator mounted in the front as intake blowing cool air to the gpus.

i mean put some fans on the side of the gpus or ontop it depends on how you look at it 


If you tell a big enough lie and tell it frequently enough it will be believed.

-Adolf Hitler 

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Posted · Original PosterOP

i mean put some fans on the side of the gpus or ontop it depends on how you look at it 

 

That's possible I do have 3 140mm fans just sitting here currently, however how would that work airflow wise, if I put them on the side pushing air into the gpu they will fight with the fans on the cooler, if I use them to suck hot air out that means there is nowhere for the fans to get new cool air from since they intake air from the bottom (which would be sucked away by the fans pushing the hot air out)

 

honestly I just left my window open to the cold and got some sweaters

 

I do that too sometimes but there is 3 problems with that.

 

1) I can't keep my window open 24/7.

 

2) It will make little to no difference in the spring/summer/fall

 

3) rain, if the wind blows from the wrong side it'll blow rain into my room giving my pc a shower. Also pretty sure increased moisture content in the air because of rain is bad for a pc regardless.

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Posted · Original PosterOP

Also about the throttling, one thing I did notice was that once I turn the fan speed down a lot (35% or lower) it will start to turn up the fans to try to keep the temperature below 100C even though MSI afterburner is still set at 35%.

 

If I had to describe it I'd have to say it's kind of like it's coughing, short blasts of turning up the fan speed (to 100% if I had to guess based on the sound) looking at those graphs from earlier it seems like the throttling does something similar.

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Instead of getting a 7990 start investing in ASICs.....


This is my Lightsaber.          {[=]////]"[¬'/\Y/#####################################
This is my other Lightsaber. (T!!!!!!!T=:"|[\#####################################  #killedmywife 

 

 

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There are NO scrypt ASICs as of yet, and BTC is stupidly hard to get into now.

I read somewhere butterfly labs was working on them


This is my Lightsaber.          {[=]////]"[¬'/\Y/#####################################
This is my other Lightsaber. (T!!!!!!!T=:"|[\#####################################  #killedmywife 

 

 

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There are NO scrypt ASICs as of yet, and BTC is stupidly hard to get into now.

https://alpha-t.net/ no butterfly labs, sorry. 

 

5mh/s for 405 euro is amazing. 


This is my Lightsaber.          {[=]////]"[¬'/\Y/#####################################
This is my other Lightsaber. (T!!!!!!!T=:"|[\#####################################  #killedmywife 

 

 

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https://alpha-t.net/ no butterfly labs, sorry. 

 

5mh/s for 405 euro is amazing. 

Doubt it's real, someone looked them up on the VAT registry, and they don't exist... So either they have to only sell like 3 top end miners, or they are going to be in some trouble.

Look up the Dogecoin subreddit (Whenever Reddit decides to work) And search for the post about them.

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