When being in the top ten at Milkyway was not enough...a third HD 7990 was added

Vester

Well-Known Member
USA team member
Today I sold the AMD Ryzen 5 2600 that I used for three months on Milkyway@home and PrimeGrid until I bricked the Biostar motherboard. Immediately after the sale, I made an offer on a Radeon HD 7990 hoping to add a third 7990 to the rack rig.

I listed my MSI R9 390 on eBay this afternoon in anticipation of getting the third 7990.

Bring on some more firepower, team. We slid from 10th to 13 at Milkyway in the past two days. [H]ardOCP and Team AnandTech passed us just when I thought we could overtake some sleeping giants.
 

Vester

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USA team member
My mining rig frame really helps keep my gear cool. The HD 7990s run 70-75 C on Milkyway without tweaking the fan speeds.

Fleet? Star Wars or US Navy? I am USN retired.
 

supdood

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USA team member
Most of that is probably because MW was the latest sprint challenge over at formula boinc. I'm guessing that their outputs will return to normal levels soon and we will have a good chance at retaking those places.

Great to hear that you're adding to the team's output!
 

Nick Name

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USA team member
My mining rig frame really helps keep my gear cool. The HD 7990s run 70-75 C on Milkyway without tweaking the fan speeds.

Fleet? Star Wars or US Navy? I am USN retired.
Gear temperature isn't the problem, 90+ degrees in the office is. :eek: I'd need to add some significant cooling to get things comfortable but I don't like to run my machines with the air on anyway. I'm dedicated but there's a limit. :D

re. Fleet, more Star Wars than Navy. The old forum had a nautical (or maybe Navy) theme and I just picked up the habit of referring to my crunchers as the fleet.
 

Vester

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USA team member
I know what you mean about the heat. The computer's best location was near the return air vent, but my wife nixed that location because of the visibility. It is now on a small desk in an unused bedroom with the door open. Our power bill actually went down this month because I put a more efficient motor on our swimming pool.

I am still winning the bid ($120.50) for a third HD 7990 with 1 day and 13 hours left. Bidding is slow on my R9 390
 

Vester

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USA team member
I was passed today by a rig with EIGHT Radeon VIIs. I didn't even see it in my rear view mirror.
 

Vester

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USA team member
I did not win the auction this evening on a used HD 7990 that sold for $185.50, but I had been watching a "manufacturer refurbished" one for $200. It will be added to my computer early next week.

The R9 390 has been removed, cleaned and put in its factory box for shipping. That auction has another three days until closing.
 

Vester

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USA team member
Three HD 7990s, six GPUs total, are running now. I lost some time today repairing and adding a second power supply. I also redid the thermal compound and gave it some cooling cycles.

I sold enough extra computer parts to more than pay for the video card. Wife 2.0 is happy.
 

Nick Name

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USA team member
Great to hear. I'm still dead in the water on MilkyWay, hopefully will have some power back on that this coming weekend if nothing else breaks. :D
 

Vester

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USA team member
Well, I've never had a computer that could approach 2,000,000 PPD. I remember my Pentium 4 @ 2GHz that managed 119 PPD! I can't do this by myself and I appreciate my teammates.

The replacement of our swimming pool pump's motor with a more efficient motor was well-timed. Our power bill did not increase last month.
 

supdood

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USA team member
That's a pretty incredible output per day! In three days, you'll surpass what I've done in almost four years of crunching. Really shows the power of GPU vs CPU computing.
 

Vester

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USA team member
CPU calculations are still important, but I couldn't resist running these HD 7990s because of their double precision performance. There are 2024 stream processors per GPU. Each card has two GPUs giving a total of 2024 x 6 = 12,144 stream processors.

The new Radeon VII is a great performer at $699 (sometimes less), and they use less power. User jpmboy is pushing 1,500,000 PPD with a single Radeon VII.
 

Nick Name

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USA team member
I was able to pick up a VII for <600, before taxes etc. It's a monster. I just have it on the test bench for now, probably won't get any serious work done until the fall. I just wanted to make sure it was working properly. After a plus 24 hour run, it crunches MW perfectly, the only errors were known faulty WUs. It does less well on Einstein, I set that as the backup project and it hung up on a couple tasks for hours. I suspect that's to do with undervolting the card but it could be a driver problem. I don't think AMD has really gotten the drivers optimized for the VII and at this point maybe they never will. Every driver I looked at had comments in the notes about some VII-related function not working properly.

I have a water block on the way and I'm looking forward to crunching MW with a vengeance in a few weeks. :D
 

Vester

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USA team member
The most recent used HD 7990, the third one, ran hot from the beginning last week. I subsequently applied new thermal compound, replaced the fans assembly, lapped the heat sinks and applied a different thermal compound. I only gained a few degrees C. I have not had a complete 24 hours of crunching since I got this card, and I began to have lockups about three days ago. With close monitoring, I found that the temperatures were up to 91-94 C. After a lockup this morning, I under-clocked the card by 15% and reduced the voltage up to 5%. Under-clocking help a bit, but temperatures were still nearly 20 C higher than the other two card's GPUs.

I believe the two heat sinks on this card are bad due to heat pipe failures. There are conflicting reports on heat pipe reliability, but I can think of no other reason for this over-temperature condition. I am going to do some parts swapping later today or this evening because I really like the performance of the Sapphire HD 7990 that runs hot. Will advise.
 

Vester

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USA team member
Sometimes, I just think too much. I swapped the heat sinks and all four GPUs are running normally. At full load, all six are running at 72 to 74 C. The one that was running hot had Gelid on it. All GPUs now have have easy-to-use
ThermaCoolFlux High Performance Polysynthetic Silver Thermal Paste | HC-180 which costs only $2.50 per gram at my local computer store. You can find it as BNYX HC-180.
 
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Nick Name

Administrator
USA team member
Great to hear there was a simple fix. I was going to ask if the fans were running as fast as they were on the other cards. I've never heard of a heat pipe cooler going bad. The only way I could see that happening is physical damage, like if it were dropped and got bent up. Gelid is supposed to be pretty good stuff, maybe you got a bad batch.
 

Vester

Well-Known Member
USA team member
I used Gelid for about five years, but it is "plastic" when spread and it gets worse after sitting in my tool box. I read a review recently that showed its heat conductance at 12.5 W/mK, the same as Noctua NT-H1. I believe I had a bad batch.

Regarding fans, I had replaced the fan kit with a brand new set when I applied the Gelid. The new fans were running about 3800 RPM. I swapped back to the original fans, too, but only to help me distinguish the three video cards.

I lost about eight hours of crunching yesterday due to a lockup. I am still learning how to configure the GPUs on this ASUS motherboard.
 
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