Bitcoin Forum

Note/Advice/Tips/Guide to those who going to buy graphic cards.

I was fooled by some other fool/fools who designed graphic cards.
2 types of card design i see & i call it OPEN type & CLOSED type. I don't know what manufactures use to call.

Example for OPEN type card is R6970 Lightning card.
http://www.msi.com/product/vga/R6970-Lightning.html

Example for CLOSED type card is MSI R6970-2PM2D2GD5 card.
http://www.msi.com/product/vga/R6970-2PM2D2GD5.html

I bought 4 nos. of OPEN type, R6970 Lightning, since it is factory over clocked to 940Mhz & also has TWO FANS.
I thought since it has TWO FANS & ITS MILITARY DESIGN, it will run much cooler than the other type.
But i was WRONG.

Actually this is foolish design to use in a multi GPU card setup. This type of cards MUST NOT be used if more than 2 cards in a pc.

In my mining setup, 6 cards are connected from slot1 to slot6 using riser cables, with more than 1 inch gap between each cards.
The LAST card in slot 6 , grabs air from open, while the card before that grabs air from back of last card & it goes on.....with FIRST card getting air from back of second card.
Here comes the problem.
The last card runs cooler(65C) & the FIRST card runs HOTTER than all (>95C)

What happens here is the last card grabs air from outside & the card design allows air to come out of the card in ALL directions.
If you look at the card, you can see there is gap in ALL 4 sides of the card for the air to escape.
The fan grabs air, pushes to the heat sink & the hot air escapes from all sides.
The card before the last card, grabs the HOT air from last card, & gets temperature increased & air escapes through all sides.
As this goes on, the FIRST card gets hottest air & so the temperature of the card is very high.
Placing 6 120mm fans on top of cards don't reduce much temperature. Only up to 85C.

Here CLOSED type works better.
In closed type air is sucked from mouth(centrifugal fan in one side of card) of the card & it passes to the GPU & comes out of the ass(back, where varies connectors are placed) of the card.
Their is NO GAP for the air to escape in any side.
This makes the air coming out of card is VERY hot. But it cools the GPU.
Since it SUCKS air, even in multi card setup, it doesn't increase the heat of near by card, since the air never escapes on sides.
Air goes out only on cards ass.

But this type also has another problem.
Since it sucks air from mouth & release hot air through ass & NO GAP for air to escape in any side, DUST if accumulated on the ass will NOT allow the hot air to go out easily.
So, it needs to be looked in to every now & then to keep the ass clean.
If not the hot air will fry the GPU & you get BAD smell.

My mining rig cabinet is made with slotted angles, just a skeleton of iron angles, same like cablesaurus A1 model cabinet.
A1 model cabinet is made with aluminium frame, mine is with slotted angles.

http://i52.tinypic.com/255qbmr.jpg



Any one object this or has some other experiences can share.
I want to know the pros & cons of the different design, so if i buy cards in future it must be a correct one.

Have you tried blowing air the horizontally, maybe push pull with fans at front and back

I've noticed a similar problem:
Closed cards (usually "reference" ATI cards) run significantly cooler than open (non-reference) cards.  The largest advantage to non-reference cards that I've seen is that they're shorter and fit easier into more cramped cases.  Also, reference cards usually run a lot louder at full fan speeds than non-reference cards, though quieter when running at the same temperature.

one option is to take the plastic off of the OPEN type and put fans to 0 speed, but only if you have a high cfm case fan(s) blowing at the top of the cards (like you have in the pic). That way you're not dealing with the gpu fans screwing up the airflow distribution. By high cfm I mean the deltas that push 150-240cfm.

Of course in a closed case you need the same thing + a case fan in front to push air in, and another case fan pulling hot air out from the back.

I usually go for the closed type because it makes ducting the air easier. But they don't actually draw air from the ass. Air is drawn in through the fan, it's a centrifugal fan. The opening on the ass exhaust as well.

For the open type, you could "fix" it by making a plastic shroud to guide the hot air out, but this tends to reduce the cooling performance for each card.
But if you plan it properly, you could offset that by directing cooler air into the intake and directing the hot air away.

I'm personally halfway through making an large airduct for my entire PC drawing all the rear exhaust eventually out the window.

I think it's just some confusion over which one we call the the mouth and the ass on the cards. :D

Just to make it perfectly clear, the only air intake is the fan, hot air is exhausted from BOTH mouth and ass of the card. That is why I said "opening on the ass exhaust as well", sorry for the confusion.

You can verify this by tearing some thin strips of kleenex/tissue paper, taping them to a pen or something and sticking it near the mouth/ass, in both cases I believe you will find the strips being blown away from the opening.

Edited 1st post to avoid mouth & ass confusion.

Ah, it is a lot clearer now that we're just misunderstanding on what's ass and mouth :D

Very disappointed. I thought this was going to be a human centipede thread with all the ass/mouth talk.  ::)

In an open case with good spacing between the cards, lots of air flow around the cards, and mild ambient air temps I haven't noticed a large difference in card temps.

In a closed case, the open style cards are a trainwreck.

This forum is about bitcoin, not human anatomy. ass/mouth used to have some fun which will REGISTER the thoughts in mind permanently.


How much spacing, you call good spacing? tell in inches. I gave 1 inch gap between 2 cards.
Lots of airflow around cards- i used 6 fans on top, not around as i can't hang/screw the fans to frame.
I used Zebronics 12v 120mm fan http://www.zebronics.net/miscellaneous_casefan.asp
The link is for 80mm. I used 120mm BLUE LED fan which gives better air than cooler master fans.
Both are priced at ~200 INR = ~ 4 USD.
Tried cooler master 120mm fan,
http://www.coolermaster.com/product.php?product_id=121
http://www.coolermaster.com/product.php?product_id=95
Both these are worst than any other fans. Giving NO air & priced same as Zebronics 120mm fan.

if you guys really can't deal with temps, just buy a SanAceF12-HHH or a PFB1212UHE. 260CFM and 252CFM respectively. Assuming that you can afford 48 extra incomeless watts.
very common fans are Cooler Master 69CFM fans. dirt cheap. moderate air flow.
the ultra kaze 3000 (144CFM) is kind of popular, but sleeve bearing won't last as long as any other bearings.

ya, i decided to buy a cooler master 90CFM fan.
http://www.coolermaster.com/product.php?product_id=6037

My 6970 Lightnings are doing just fine...   ;)



http://i56.tinypic.com/8xtt38.jpg

http://i56.tinypic.com/2nuj9dw.jpg

only a 69.69 CFM by default (12V molex).
The 90 CFM figure is taken from an overvolted fan.

Damn.

What fan, the black one behind the mother board, you using?
I think, its a sucker fan. Sucks hot air coming out of card ass & sides.

I'm using Vornado 630b fans for 3 of the shelves and cheaper Honeywell fans for the bottom shelf (it's colder down there).  The fans on the left are pointed sideways to draw cool air into the room and pull hot air from the hot cards on the left.  The fans on the right are blowing across the cards.  The hot air is exhausted out the window (about 7500 watts of heat).

FYI, the "closed" type is known as "reference design cooler" and "open" type you refer to is called "non-reference design". the ass and mouth term you used is hilarious for video cards  :D

HIS make plenty of "non-reference design" which are closed. Most famously, their IceQ coolers.

funny i have only open cards and with a little more than 3 inches they run much cooler (10-15c cooler) than the closed.  Of course i only have two in these rigs.

I'm running only 2 of 4 cards, numbers 1 and 3 (numbering 1-4 from left), but with this (https://i.imgur.com/1C7HL.jpg) setup (https://i.imgur.com/KEQtN.jpg) I'm getting temps in the 66-71 range. These are the "open" style ones, right? (Sapphire 100282 Xtreme)

Yes those are open type only.
You using 5850 card which may be giving less heat & less hash. Also you have placed with more than 2 inch gap, that gives enough space.
I also think your room temperature & city temperature is in the range 20C.
Is it? 

Non-reference or "Open" cards are great if you have enough airflow.

I have a, few, fans...

http://farm7.static.flickr.com/6143/5918122770_7a8be18a2a_z.jpg

With the side panel on my case, I also get a 140mm fan blowing directly on the cards.  

Like so:
http://farm7.static.flickr.com/6132/5917556621_0c7d373e23_z.jpg

Temps at 975Mhz are between 67-72*C with GPU fans @ 50-60%

For 2 card setup its ok.
For 6 or 8..?

You're correct. This has been proved in server chassis design.

However, the gpu manufacture does not take mining rigs to consideration. They designed the cards for xfire or SLI. It has been proven to be very effective.

I'm with you tho. I like the ref design better. Just like how i like server chassis design with blower fan