I ran both samples, and I do see the memory increase in both. The second doesn't crash because it runs x64, so there's a lot more headroom to work with. However, I see the memory leveling off somewhere around 1Gb and not climb any longer (without your code that allocates extra memory). I changed the refresh interval to 10s to really push the limit and ran for several hours, and memory did stop climbing (in fact it topped out at 1.2Gb then settled into 1Gb and stayed there).
I think what you're really hitting here is that you're loading a lot of data, and constantly refreshing all that data does require some memory to store and process. If you're going to display a significant amount of data and process it, I'd recommend you make sure your application runs as x64, since a 32bit .NET Framework process generally don't like you to exceed 1.2Gb of memory use. With the data and the processing itself required a good gigabyte of memory, it doesn't leave much room for the rest of your application.
