Electronic noise in gfx cards is pretty hit/miss depending on your particluar system. When you say you are looking for a step up...is it for gaming? If so, what games, monitor resolution, picture quality levels, etc? At the moment, the top end passive is the AMD HD7750. There are some very quiet fanned cards as well if you need more of a performance bump.
If you are considering to replace your CPU sometime soon - the integrated GPU in the current gen of Intel and AMD CPUs are faster than your 8600GTS and use in the neighborhood of 10-20W vs the 70W of your card.
Thanks for your reply. Yeah the plan is to replace my CPU and motherboard as well. So the integrated GPU's are that good? You know which integrated GPUs are best? And how does it work? I assume the actual connectors are on the motherboard? Can you get two-screen output from those too? I suppose I should google some on that, but it's always nice when someone explains it...
Well, actually, I am running a Hackintosh that I use for my work, which is video editing and After Effects/Photoshop work so, thats the most important part. However the newest OSX versions have real trouble with older Geforce cards... so thats the main reason I'd like a more modern card. So no, I am not looking for a heavy gaming card really, but when I am upgrading it would be nice with something a little better, if I can run Civ 5 with a decent framerate I'd be happy. My 8600GTS can barely manage it, but the framerates are pretty bad... But like I said, since I made my system so silent that downside of that is stuff like high pitched whine gets really noticable and annoying. So mainly I wanna get rid of that problem in my new system.
I looked at the Sapphire HD7750 and figured out, like you said, that it seems to be the best passive card in terms of performance, although the review here does say it comes with a little whine, but maybe not much. I might go for a CPU with good integrated GFX and then try a few video cards as well... and return them if they make some annoy noises. Not sure... I'll definitely need to learn more about integrated GFX. Its new to me. I am thinking about an i5 or i7... but if AMD have better integrated GPU then maybe I'll consider AMD. In the core 2 generation it used to be that Intel was generally the best CPU, and also came with less power consumption and heat output. Not sure if that's true today as well?