The G400 has a "Vertical Scan Range" of 48-120Hz; the vertical scan range is the refresh rate, and since the maximum is 120hz, it means you will be getting 120hz at the lowest resolution (which is most likely 640x480).
http://www.ita.sel.sony.com/products/displays/corp/cpdg400.html
The E400 has the same vertical scan range (48-120Hz) as the G400, so, once again, you will be getting 120hz at the lowest resolution (640x480).
http://www.ita.sel.sony.com/products/displays/soho/cpde400.html
It looks like these monitors are tuned for the higher resolutions. They have pretty impressive refresh rates at the higher resolutions (1600x1200 @ 85hz) but a maximum of 120hz at the lower resolutions is pretty mediocre. My 17" monitor only gets 75hz at 1600x1200, but it gets 160hz at 640x480, and 140hz at 800x600. So, if you're planning to run it at 1024 or less, you might look for a monitor that is tuned more for that end of the spectrum. Just look at the maximum vertical refresh rate (or "vertical scan range"
![Wink ;) ;)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
; whatever the maximum is, that is what you will be getting at 640x480.
Keep in mind that your video card has to be able to keep up with the refresh rate. Check the specs on your video card for the refresh rates it can draw.