Zotac GTX 780 OC: swapping fans for more CFM & pressure?

[magellan]

OK, I just got in a new Zotac GTX 780 OC. It has a non-reference cooler that has three chintzy, low speed fans on it. What I'd like to do is take off the entire shroud and fan ASSY and put on:

a. either two or three high power 92mm x 32mm shrouded fans
b. three high power 80mm x 32mm or 80mm x 25mm shrouded fans.

I'm hoping to source some fans that'll run at ~4K to 4.5K RPM.

Then maybe do some mods to the BIOS to up the TDP limits and try
some overclocking.

The aim is to double the performance of my o'clked 6970 (which can run
any title @ 1025/1415, and some games higher than that).

 

[nicspits]

I recommend removing the entire cooler when you do this. I found the extra fan coverage coming away from the motherboard to get the hot air past the card and towards the case exhaust.

I used to put a couple layers of electrical tape (double sided) around the outside of the heatsink to insulate the heat from the future heatshrink tubing, which I would wrap around, secure with epoxy and super blue on the motherboard side of the cooler, and get the lip of the tubing around the fans. The fans would be stood off with little pads of neoprene to avoid vibration\noise (super glue attached).

So once the unshrunk heatshrink tubing is just enough to sit there, around the fans and covering most of the electrical tape wrapping, gently and evenly, with a finger on the super glue point, shrink it around so it tightens up and puts just enough pressure on the fans to keep them secure, be careful not to do it too much and have it retract past the edge of the fans onto their side (this can be remedied with again, super glue).

once they're snug enough to not shift when you turn the heatsink over, feel free to use nail polish or whatever you want to drawn on\color the "shrink shroud".

It looks like the zotac cooling unit is pretty thin so be sure not to get high cfm fans, probably 32CFM 21dba 80mmx20mm would be great. If you get the thicker fans, they'll be too much force and it's just going to create a lot of vibration with the air blowing right back on the blades, it has to be allowed to escape. (I once experimentded with 3 70s, and the center exhausting with a modified Dell directional cone, worked pretty well with the side fan exhausting too, too bad that was back in ATI 6970 days.)

 

[RnRollie]

Or get this + some hose

 

[EarthDog]

The aim is to double the performance of my o'clked 6970 (which can run
any title @ 1025/1415, and some games higher than that).

Then maybe do some mods to the BIOS to up the TDP limits and try
some overclocking.

A couple of things...

1. You will not double the performance of a 6970 (even at stock speeds) with ambient overclocking on a 780. You will not gain 45%+ increase from overclocking the GPU.
http://www.techpowerup.com/reviews/NVIDIA/GeForce_GTX_780/26.html
2. I believe all non "AMP!" versions of the Zotac 780 are reference models... so I would be careful with modding TDP's and adding too much voltage.

As far as the fan idea...that is your choice if you want to ghetto mod your cards up for an unreachable goal. Now, for giggles, have at it.. But for your goal, there is no chance.

 

[magellan]

ED has put the final nail in this coffin.
ED, as far as the risks of adding more voltage and increasing the TDP limits, is this
risk primarily to the VRM's?
I only ask because I noticed w/my 6970, that adding a powerful fan blowing right
on the VRM's seemed to allow me to increase my overclocks to over 1025Mhz on the
GPU core, whereas before such speeds resulted in a hard lock.

It looks like the zotac cooling unit is pretty thin so be sure not to get high cfm fans, probably 32CFM 21dba 80mmx20mm would be great. If you get the thicker fans, they'll be too much force and it's just going to create a lot of vibration with the air blowing right back on the blades, it has to be allowed to escape. (I once experimentded with 3 70s, and the center exhausting with a modified Dell directional cone, worked pretty well with the side fan exhausting too, too bad that was back in ATI 6970 days.)

I was planning on putting 25mm thick output shrouds on all the fans.

Your idea on the 70mm center fan exhausting is interesting though.

 

[EarthDog]

Primarily, yes.