I broke a fan blade on my MSI GeForce GTX 650. I looked for a replacement but I couldn't find the same one. I read that I might not need a fan and just the heat sink is enough, I don't run it too hard. Do I need a new fan and how do I find one that fits? My old fan was 90mm in diameter and it snapped over the edges of the heat sink which is 92 x 107 mm.