Well actually nVidia System Utility is a realtime overclocking utility made for nForce 2 chipsets among others.
I took the liberty of supplying a few screenshots here simply to give proof.
http://upl.silentwhisper.net/uplfold...inxp2gbram.JPG
http://upl.silentwhisper.net/uplfold...systemutil.JPG
As you can see I am currently using 2gb RAM on my nForce 2 motherboard as shown by windows, POST and so on.
About speed, as you can see on the second picture (nVidia System Utility) the RAM frequency is currently 399MHz DDR @ CAS 2 with the other timings as you can see on the picture.
nVidia System Utility is a program developed by nVidia and is free for download. It supports real-time monitoring of voltages, speed and temperatures. It also supports real-time changing of voltage, FSB, Timings and more.