Draging the image in Bridge Slideshow at full mag. has become very slow with time taken to render the image after each drag ~ 5 to 7 seconds, specially with raw files. Both JPG or D300 NEFs. I have no other programs running excetp Trendmicro internet security.
Sytem : Intel core2 3 GHz, G33 chipset, 2 Gb ram 256MB On onboard Graphics. CS3, ACR 4.6,

Where might be the bottleneck? How to speed it up?

This is usually a video card problem that is not robust enough. Enable software rendering in Bridge and see if that helps (edit/preferences/advanced).

This option unexplicably disabled on my machine!!
Anurag

It appears that your video card does not support that option. Might research your video card for memory, speed and capabilities and make sure you have latest driver updates.

I have the onboard video card of the Intel G33 mother board to which I have alloted 256MB.
Apart from video card could any other cause be there. What about antivirus software?

It is always possible that other software can slow the process down. Open task manager and see what is running. Can try closing applications and see if it makes any difference.

The most likely suspect is the video card. With the video card on the motherboard I believe that uses shared resources with the OS, which means you have less than the full memory to use for either function. This is a space and price saving compromise, but does degrade performance. No free lunch.

Any good Video cards you can recomend?

If you ever envisage moving up to CS4, pay a lot of attention to the video cards that work with it. CS4 is much more demanding.

There are several threads in the main Photoshop Windows forum.