I recently purchased an Asus GTX 770, and it sags in my system. Therefore, I used a zip tie on a notch on the black frame of the video card and I attached it to the top of my case with a link of zip ties to provide the card support. My question is will the zip tie tolerate the heat of the video card? How hot does the surface of the video card itself get? I read online that zip ties are made to withstand temperatures of up to 85C but have a melting point of somewhere in the range of 200C. After reading online, it appears others have used zip ties to provide their GPU support as well. Mainly, I just want to make sure that the zip tie can withstand heat from the GPU.
Don't worry about it. You're not going to melt the zip ties before you melt the card. However, it the tie directly contacts one of the card's heat pipes when the card is at its peak stress/heat, it could soften the plastic a bit. What concerns me though, is why you need a support for your graphic card. If it is fastened to the rear of the case with its two screws, it shouldn't need added support.
I took a look again, and it appears the zip tie doesn't make any actual physical contact with the heat sink. It is just very close to the heat sink. The zip tie is on the bottom frame. I have the gpu fastened with the screws, but the far edge of the card still hangs down a lot. I figured it would be best to give it some support.