I already upgraded the stock Northbridge (NB) heatsink on my ASUS A7N8X to a Zalman ZM-NB32J passive heatsink. This time, I swapped the Zalman passive heatsink for a Vantec active HSF, as included in the Vantec Iceberq kit.
I'd seen a lot of forum activity regarding the removal & swap of the NB heatsink, so decided to snap a few pictures to try and help others see that it's quite a simple process.
The most common problem people have with removing the stock (and Zalman) heatsink involves understanding the "push-pins" used to mount it. The push-pins go through the motherboard, so you need to have access to the rear of the board to remove them. This will generally involve removing the motherboard from the case/tray to expose the pins.
Push-pins from rear of MoBo
You need to squeeze the 'flare' to push it through the board, at which point the heatsink is held on by the thermal compound only.
The stock heatsink uses pink "bubble gum" compound to attach it to the NB chip. Because I have already changed this once, this picture shows the Arctic Silver compound I applied when I made that swap.
The Arctic Silver is not sticky, unlike the bubble gum which glues the chip and heatsink together pretty firmly. To remove the stock heatsink from the NB ship, you need to apply some heat. I used a hairdryer and gave it a good blast before prying the heatsink loose. You have to use quite some pressure to get it off, and I found a twisting motion seemed to work best.
Once the heatsink is removed, you'll have your NB chip exposed, but caked in compound which must be cleaned off using the appropriate cleaning compond. I use Isopropyl Alcohol (available from Maplin here in the UK) to clean up any reside, which should leave you with a nice finish as shown above.
Northbridge and Southbridge chips.
Once you have the NB exposed and clean, you basically reverse the process process to fit the replacement; apply the thermal compound of your choice, seat the cooler and re-push the new pins through the holes in the motherboard to secure it.
Vantec Cooler installed.
Note: In a couple of the shots, the nForce2 Southbridge is also clearly visible (labelled "MCP-T"). I attached one of the heatsinks from the Iceberq kit to the SB using a thermal pad from the kit.