So pretty much three heatpipes connect to the GPU block and then transport heat to the cooling ribbons on the back.
When you look closely at the the cooler you'll see the pipes and aluminum cooling ribbons. An internal coolant is inside these pipes (air/gas/fluid/whatever floats the boat) and flows from the GPU chamber towards the cooling ribbons where heat will be dissipated with the help of airflow. The cooling method is all based around circulation. Although we just named it gas the coolant can be something else or actually change into a gas. Usually it is liquid when cold but easily becomes a vapor when heated and vice versa.
As heat is absorbed from the processor (GPU), it will follow the path of least resistance to the aluminum fins, where the heat then dissipates.
For that heat to dissipate you'll definitely need some active cooling as you do not want that residual heat to hover around the cooler or anywhere else in your PC.
Sparkle GeForce 9600 GT Passive review I had a peek around for an exotic model GeForce 9600 GT. I ended up with Sparkle .. get this .. 99 EUR for their passively cooled product with 512MB GDDR3 memory. I'm sorry but that's just a heck of a lot more value than the 9500 GT will offer gaming performance wise. And next to that, as this review will show .. the product has a few surprises ready under it's sleeves.
Sparkle GeForce 8800GT Cool-Pipe3 512MB review Sparkle recently released a GeForce 8800 GT that actually is passively cooled. Because the reference cooled 8800 GT already runs insanely hot to 90 degrees C, doing the cooling part passive .. would definitely make things even worse. Combine that with the rumored GPU core temperatures of 110 Degrees C I pretty much stereotyped the product even before we had tested it.
Sparkle Calibre P880LV GeForce 8800 320MB Much like other companies out there with a special edition card, the Calibre series is slightly more expensive yet you'll receive some pretty nifty extra candy. In the case of the GeForce 8800 GTS 320 MB they are offering your an overclocked model armed with nothing less than a peltier cooler.