Hi all,
Here is a post that I put on a Litecoin mining forum about how you can
kill your gpu in less than a year by starving it for air and having one
gpu next to each other and running it at heavy load all the time. I
thought you guys might like to see it. While most people don't run
their gpu's 24/7, this is still good info to know. I've condensed it
and stripped out the mining specific parts and left the generic parts.
Here is the full post if anyone want's to read it.
https://forum.give-me-coins.com/index.php?p=/discussion/666/heat-death-how-to-kill-your-gpu-in-less-than-a-year#Item_2
----------
I've been mining Litecoin off and on. I'm using gpus. I wanted to post
some info about killing (or not) your gpu fans. Basically, if the fans
fail, your gpu is out of commission. The problem is that gpu's are
designed to run a few hours per day at heavy load. They are not
designed for 24/7 operation with the fans at 100%. I have personal
knowledge that running the fans at high speed on a couple of particular
cards will kill them in less than a year. I've had this happen on the
MSI 7850 cards with the Twin Frozr III cooling system. RMAing these is
a pain and I have to pay shipping so I'm phasing these out of my
system. I think their 7870 cards have the same design. (Actually MSI's
warranty procedure is fairly painless, but uninstalling and packing and
shipping and reinstalling is a pain.)
The FAN WILL NOT RUN AT EVEN 85%, much less at 100% for a very long
time. The fan is the weak link. You HAVE TO PROTECT THE FAN(S) FROM
PREMATURE DEATH if you're running the gpu's for extended hours or if
they don't get much air flow.
I'm totally making the following numbers up. But, say the fans were
designed to run for 4 hours per day at high speed. If you're running
24/7, which is 6 TIMES more, the card will fail 6 TIMES sooner than it's
original design life. If the design life is 3 years, that works out to
a failure after about 6 months, which is about what I experienced.
The problem is the air gap between the cards. Most cards have the fan
intake on the side. When you put two cards side by side, there is very
little air gap between cards to allow air flow. If the motherboard is
vertical, as in a tower case, any card which is on top of another will
not be happy. According to the ATX spec which I looked up, there should
be 1.6" between two double width cards (circuit cards). If the cards
are almost 1.6" thick, there will be NO ROOM for air intake for the
fans. This will make the fans ramp up to maximum velocity striving to
draw in some air and maintain the temperature target. Thus, the fans
wear out. The thinner the card you can get and the more efficient it's
cooling system, the longer they will last. Generally, the bottom card
next to the power supply will have more air flow anyway. If you have a
card that you know is weak, you can stick it down there. That way, it
can work with less fan velocity.
When I was looking around for new cards, I found one Gigabyte card that
had specs of 1.7" thickness. That one may not even fit in the
motherboard beside another card. Even if it did, it would get no air.
I'm not buying that one.
I'm phasing out the MSI 7850 Twin Frozr and 7870 Twin Frozr cards. They
are very thick. When in adjacent slots, they have very little space
between them and they kill their fans quickly.
I have some Asus 7850 cards with their DirectCU cooling system. These
cards are noticeably thinner than the MSI's and the fans run noticeably
slower, say in the 40-50% range, to keep the card cool even when they're
adjacent and running at full load. Even then, there is a visibly larger
air gap between them. I haven't owned them long enough to know when
they fail. But, since the fans are running much slower, it should be
much later. If you give them an even bigger air gap, they love it. I
currently have one running overclocked from 860 MHz original to 1000
MHz, with several inches of air next to it, running at a cool 70 deg C
and 20% fan speed (which is my minimum).
In considering new cards, I would stick to manufacturers with a 3 year
warranty or more. That pretty much limits things to Asus and MSI as far
as I know. XFX has some sort of lifetime warranty but it seems like
there are lots of catches when you read the fine print. If you want to
put cards adjacent to each other in a motherboard, don't get anything
thicker than 1.5" (rounded off number). Thinner is much better. I
would never buy a card for heavy usage without dual fans.
Based on reading specs only, but not experience yet, I like the new Asus
and MSI R9 200 series cards.
The Asus (R9270) cards have the DirectCU II cooling system.
The MSI (R9270) cards have the Twin Frozr IV cooling system, a version
upgrade compared to the cards I own.
I did a subjective comparison of an older MSI 7850 and an Asus 7850 by
running the fans on each one up to 100% one at a time. To me,
subjectively, the MSI card seemed louder. I did not do any
measurements. However, if you keep the fans at 30% - 50%, this will be
a non issue.
Note that I'm NOT recommending to LIMIT the fan to 50%. I'm still
setting my upper fan limit to 85%, and the card will probably bump it to
100% if the temperature exceeds the overheat number.
I AM recommending to buy a thinner card and give it enough air space, if
possible, or overclock it less, so the fan never has to exceed 50% or so
to keep the card cool.
If you look at your card in gpuz in Windows, you can find the default
clock frequency, always a good number to keep in mind. You can also
look at the specs. If you're running Linux, and the ATI driver, you can
issue this command:
aticonfig --adapter=all --odgc
That stands for overdrive get clocks. It will give you a list of the
current clock settings and loads. It will also show you the adjustable
range for that card. I don't know how rigid that is, but it is at least
a guideline.
The Asus 7850's, for example, have a default clock of 860 MHz. They
have an adjustable range of 300 - 1050. I normally run them at the max
of that range, adjacent to each other, and they have no problems at
all. The fans on the hottest card are running about 50%. That's not as
good as 30%, but it's much better than 85%.
So, the bottom line for how to improve your gpu life, assuming the fans
are the weak link, is not to run the fans too much. Buy cards that
allow space between them and that have very robust cooling systems. Try
not to put cards adjacent to each other. If you're running cross fire
or sli, maybe you can get a longer bridge cable. I think new setups
don't require bridge cables, but I'm not sure. Try to let the fans run
at less than 50%, but don't force that to be the max limit, in case the
card overheats. If you notice a fan running really hard, try to find
out why. Maybe one has failed, or maybe a case fan has failed, or maybe
the intake vents are clogged. If at all possible, use a case with
filtered air intakes.
By the way, regarding case fans:
High velocity case fans are your friends.
Good:
Corsair Air Series AF120 Performance Edition CO-9050003-WW 120mm High
Airflow Case Fan
http://www.newegg.com/Product/Product.aspx?Item=N82E16835181022
Better:
Cooler Master JetFlo 120 - POM Bearing 120mm Blue LED High Performance
Silent Fan for Computer Cases, CPU Coolers, and Radiators
http://www.newegg.com/Product/Product.aspx?Item=N82E16835103192
There are ways to move your gpu's up and away from your motherboard, and
adjust your spacing with riser cables, but I haven't tried it.
This represents most of what I've learned the hard way. May your way be
less hard.
Sincerely,
Ron
--
(PS - If you email me and don't get a quick response, you might want to
call on the phone. I get about 300 emails per day from alternate energy
mailing lists and such. I don't always see new email messages very quickly.)
Ron Frazier
770-205-9422 (O) Leave a message.
linuxdude AT techstarship.com
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