Video cards hung upside down

[setishock]

I like my video card and don't have any problems with it. EVGA Nvidia GTX650ti.

I had to do a total tear down of my system after an 8 month absence. My AC got swapped out for a POS and there was mold and mildew every where. And worst of all in the case.

I wound up having to completely take apart the video card to clean it. It was awful.

But while I was working on it I got to thinking why are video cards hung upside down? Heat rises so it would make better sense to have the heat sink and cooling fan facing up. But since it is what it is I'm thinking of replacing just the fan. The current fan is mounted on a bracket that is an integral part of the shroud.

Being this way if I wanted to replace the fan it would have to screw directly to the heat sink. So the mounting bracket made in to the shroud either would have to be cut out or simply the shroud would have to go.

As you can see in this picture the heat sink has 4 arms that end in a claw like structure. I would venture based on their appearance, they are for mounting screws. These are not the mounts for the heat sink to this board so they are free to use.

The predrilled holes where the shroud screws down are in the same location as the screws to hold the heat sink to the chip. This simplifies the manufacturing process. But take note of the fins being trimmed on the top, bottom, and more so on the left side. So it is keyed to how it goes on.
Also take note of the "tuning fork" fins. This is the same concept as Intel uses on their OEM CPU cooler. The forks give more surface area exposed so more heat can get dumped off. The down side to that concept is the more air you force through the forks, the more they vibrate. They actually hum as the fan ramps up. They vibrate and in turn vibrate the core and the core being screwed to the board, the board acts like a loud speaker.

So having said all that my only question really at this point is 2 fold.
1> What is the spacing on the claw end screw mounts?
2> What is the spacing on the screw holes for the shroud where it screws down the heat sink?

I don't have a metric ruler is why I'm asking. If I find out the spacing I can then order an aftermarket fan for it. (There isn't enough clearance for an aftermarket cooler.)

 

[S0ULphIRE]

The fan is blowing air into the heatsink, which means it's drawing air from the bottom where all the cool air is. If you mount it the other way around it'll still be pushing air in, but it'll draw from the air on top of the card which is going to be (theoretically) hotter. Why do you want to do that?

 

[raverx3m]

most of the home built systems don't even have the proper airflow inside the case anyway

 

[setishock]

@ SOULphIRE
Well you can't change how the card is mounted. And what you said makes perfect sense.
I want to swap out the fan as I think the mounting bracket is blocking a goodly portion of the incoming air. If the fan is replaced with one the right size and mounted up on some sort of stand off, there would be nothing in the way of the air flow. Might be a little bit more efficient. And with that comes lower fan speeds which translates in to lower current draw and a lot less noise. The one thing that does have me puzzled is why do they use a voltage controlled fan? Makes shopping for one that uses 2 wire and in the same or close milliamp range interesting. But I really need to know the spacing of the holes on the arms and the ones near the middle of the heat sink.

@raverx3m
You're right. My case is not your typical case. It has a 120mm x 240mm passive intake with 2 120mm fans in the roof and 1 120mm fan in the back opposite the heat sink fan. The heat sink fan draws air through it instead of forcing air in to it. I've been of the school that when you try to force air in to a confined area like the small spacing between fins, you get a pressure build up and the efficiency goes down. Even with high pressure fans like the Cougar Vortex series, you can only push so much air through. By drawing air in you create a low pressure area in between the fins and air gets drawn in with out being forced.

I got my CPU down to 69F last night. I'd like to see where I can get the video card temps down to under low, medium, and high loads. I'm always on the look out for ways to get the temps down on just air that any one could copy and make use of.

Thanks for the input guys. I'll keep you posted on what I find out.

 

[carnageX]

@ SOULphIRE
Well you can't change how the card is mounted. And what you said makes perfect sense.
I want to swap out the fan as I think the mounting bracket is blocking a goodly portion of the incoming air. If the fan is replaced with one the right size and mounted up on some sort of stand off, there would be nothing in the way of the air flow. Might be a little bit more efficient. And with that comes lower fan speeds which translates in to lower current draw and a lot less noise. The one thing that does have me puzzled is why do they use a voltage controlled fan? Makes shopping for one that uses 2 wire and in the same or close milliamp range interesting. But I really need to know the spacing of the holes on the arms and the ones near the middle of the heat sink.

Why wouldn't you want a controllable fan? Then you can manually do exactly what you want: lower the fan speed which makes less noise and consumes less power. You can control it via software then (or the drivers will manage the fan speeds for you if you don't set custom fan curves).

 

[Joe C]

Just get a BTX case, your GPU will be facing up and it'll be a lot less trouble... that is if you can find one and that isn't too ugly
New Dell XPS 700 Computer Chassis Case Without Power Supply | eBay

 

[setishock]

I do want a controllable fan. The reason I asked about why they use a two wire fan is the rest of the fans in my system are all 4 wire. PWM, tach, and power. With just regulating voltage to control the speed you get no RPM feed back. All the PrecisionX software says is the fan is going so much percentage. Like for example, it shows 21% at Idle. 21% of what? I would much rather have a 4 wire type fan. But since it doesn't have it I turned my attention to how the fan is mounted to the shroud and how the shroud is mounted on the heat sink.

There is way too much plastic in the way. Surface area of the heat sink is being blocked.
What I proposed and based on SOULphIRE's description of why the card is mounted upside down, is to make use of the mounting holes at the end of the heat sink in the corners. This is the picture I sent to EVGA requesting the spacing on the holes in red and the OEM mounting for the shroud.

What I propose is taking brass stand offs like your mother board has and screwing a set of 1/2 inch to the holes marked in red. Then in to the brass screw in short nylon stand offs. The nylon would act as vibration dampers. I think the brass being in the air flow would stay cool enough to keep from melting the nylon stand offs. Then screw the fan down and power it off the card.
Being a much larger fan, and I'm thinking it's going to be 90 or 92mm, will be able to move a higher CFM at lower RPM's. When the GPU gets loaded up and the heat sink gets warmer the fan won't have to rev up as much as its smaller counterpart did to cool down the heat sink.

When EVGA gets back to me with the hole spacing information, I'll be able to get the stand offs and the right sized fan in one order.

 

[setishock]

I guess since there hasn't been a response at the EVGA forum I'm going to have to take the card out of the computer and tear it down again. Frack!

Plain and simple I want a corner mounted fan so the OEM bracket are removed from the air flow. The more air moving across the heat sink the cooler it will be.

 

[carnageX]

If you're so concerned with it, why not just get an aftermarket GPU heatsink/fan?

 

[setishock]

I like to roll my own solutions like I do with my models. But until I get an answer to my post at the EVGA forum I guess I could shop for one.