Another user (or maybe it was you) has the same issue with the same camera model as described in
the thread at this link.
FWIW, there's a driver on the Asus download site
(link) for your camera model (VID_13d3&PID_5122) dated Jan 25 2011 version V5.8.55133.208. Have you tried that?
I'm not sure if it's just that camera model or a software issue. The camera on my G73JH certainly doesn't have any issues but it's a different model from a different vendor ID...I would have noticed right away as I develop camera software. I can get 30FPS up to 800x600 and 15FPS up to 1600x1200 (2 Megapixels) with no more than the usual <1S latency in preview.
To rule out software you could try this app called AmCap
(link)...it's a DirectShow demo app from the Windows SDK so the UI isn't pretty but it uses the camera raw - no filters or frills. You can try different resolutions and frame rates to see if it's any better than the capture apps you've tried.