How-To make a fanwich — Brian Berryman
After seeing a couple of articles detailing how to mount a fan to the back side of a video card recently, I’ve had this in my mind to try out.
I had the case apart the other day, upgrading a couple of exhaust fans, when I thought “Now is as good a time as any to try this”. I did some digging through my hardware/junk drawer, looking for some nuts and bolts to use to mount the fan with, and came up empty handed.
- An empty set of GPU heatsink mounting holes available on the video card;
- Two threaded motherboard mount standoffs;
- One 50mm fan (3 or 4 pin lead, doesn’t matter, as long as you can plug it in);
- 10 minutes time (if you stop for a cigarette and bathroom break).
NOTE: Use all normal and necessary precautions to avoid damaging your video card while handling due to static discharge. Use of a wrist ground strap is recommended.
I had swapped out motherboards in my main rig the weekend before, and like the true lazy person I can be…had yet to put away the extra motherboard mounts from the swap. The board I replaced was wider than the replacement and used an additional three mounting points – these standoffs were still sitting on my workbench.
These motherboard standoffs actually thread into the tray, replacing the traditional metal mount and screw usually used for attaching the motherboard. They looked like just the ticket:
Now, this trick will only work on a video card that either has a 2nd set of unused mounting holes around the GPU, or the HSF is glued onto the GPU, and the holes are free. There needs to be an open set of holes around the GPU to perform this modification.
The threaded end of the motherboard standoff will insert into the open set of holes in the card. It’s a bit of a tight fit, which is good as they won’t easily fall out. A bit of a push and twist is used to get them in the holes (along the lines of “threading” them in, but pushing at the same time).
While this certainly won’t damage the circuit board of the video card, I don’t know if the standoffs would be able to thread back into a motherboard tray after using them like this.
Let’s walk through the whole procedure – it takes just a couple of minutes. It took me longer to take the pictures than to actually perform this modification.
Here’s the back of a Hercules 3D Prophet II MX card…a very common graphics card and a good one, in my opinion. Getting a bit long in the tooth, and certainly not “cutting edge” anymore, but still an admirable performer with a reputation for overclocking exceptionally well.
You’ll see the two holes that are used for the GPU HSF, and right next to them is a 2nd set of holes (marked in red). Here’s where we’ll mount the standoffs:
Holding the card by the edges, with the back side facing you…
…insert the standoffs into the holes. Push, twist and they’ll go in. Watch the front side – if the holes are located under the HSF, stop pushing when the threaded plastic end touches it. If there’s nothing above the holes, seat the standoff fully.
There’s one. Now install the second one in the other hole the same way:
With both standoffs installed, next comes the 50mm fan. You just set it right on top of the standoffs. Just a slight push fit and it will sit down on the standoffs, nice and snug:
The standoffs keep the fan above the card, allowing airflow to move freely. Since these standoffs are plastic, there’s no chance of shorting anything out after inserting them. And, unless you plan on transporting the PC anywhere or turning it upside down, that fan is going to stay put. Now you have…
The card in these last pictures is my PNY Verto GF2 MX 400. It’s in my “main” rig (That’s my “voltmod” pot on the left, another story, another day…). I had this fan already installed when I decided to write this.
So, how does it work?? Let’s take the fan off for a moment and check the temperature of the back side of the GPU. I used a Raytek MiniTemp (MT4) to measure the temperature – a really nice, accurate device. When this (and the next) picture were taken, the only programs running on this machine were Folding@home and the WebCam program itself.
So I guess you could say the temps are at “idle” – I’m not running anything 3D intensive. If you look closely, you can see the small red dot on the back of the card where the laser is reading the temperature (just to the right of the MT4):
Now let’s turn the fan back on and see what the temperature does. I’ve had this 50mm fan forever – I took it off of the HSF from an old first Generation Pentium rig. I don’t know the specs on the fan – the only info written on it is “CPU Cooler ‘KWI’ ball bearing”. I doubt it puts out more than 5 to 7 CFM. Here’s the “after”, with the fan mounted and running:
I think that’s a pretty impressive drop! I did hit a slightly hotter spot on the card, but the highest I found was 33C. That’s an 11 C drop, which is about 25%. For a couple of minutes invested and having the parts already available, I couldn’t go wrong.
- Completely reversible, and does not damage the video card in any way;
- The standoffs are made of plastic, which removes the chance of shorting anything out;
- 25% reduction of back side GPU temperature – this can only help the front side GPU HSF work better;
- The fan can be removed and installed without removing the video card from the motherboard (although I’d recommend installing the standoffs initially with the card out);
- No glue or goop required. – clean and dry.
- So far, the only supplier of the standoffs I can locate sells them in packs of 50 pieces for $9. But I’m still looking….
- A 50mm fan costs just about as much as a much larger one. Unless you happen to have one handy, the cheapest I’ve seen thus far is about $6.
But, when all is said and done, you’ll have a video card that is capable of….
Brian Berryman (aka “Mr B”)
For more information on the Raytec MiniTemp MT4;
The motherboard standoffs can be found here;
50mm fans can be found here;