I'm running Oblivion and I don't see any difference between 1 GB and 2 GB of memory. of course i haven't tested it for more than 5 minutes but the initial load is just as slow as before.
does anyone else see a difference between 1 to 2 GB of RAM?
Make windows unload the pagefile, then after a reboot let it load again using a "system managed size" or fix it @ 1.5 times min/max your ram and see if that makes a difference
Just adding another GB of ram will not magically make your load times any less, there are other factors involved (with Oblivion the CPU will be the biggest factor after GPU, in some areas even more important than GPU).
Many parts of the game are heavily based on the CPU, as of now you will notice the biggest change in Oblivion with different processor speeds.
This is why many people dont see a change of framerate with more ram, or with changing the resolution, cause its CPU limited.
It won't help with load time, but it should help with stuttering during gameplay since it won't need to hit the pagefile on your hard drive (I've seen over 1.2gb of memory usage playing Oblivion).
Oblivion won't take advantage of mroe memory too well on it's own. You can read up on the web on how to mess with the proper .ini file settings in detail. Here's a link to the tweakguides page talking about memory settings in the ini file.