Q:

Why does it take more time to write a photo to memory when I shoot in RAW?

I've a Sony DSC-F828 and when I shoot in raw it takes a lot of time to write to the card. Is this only because the file has much more data? 
Will connecting the camera to a PC reduce the time it takes to write one photo to disk? Or using a buffer?

A:

RAW files contain more data than JPEGs so saving/moving the files takes more time. The RAW and JPEG files should be the same resolution, but per pixel there is more data. 
Connecting to a PC isn't going to make it take less time; it may actually take longer because the speed of writing to the SD or CF card is probably faster than the USB connection to the PC. 

A:

There are three factors that determine how long it takes to save a photo to the memory card:

The time it takes to compress the data into a file.
The size of file.
The I/O speed.

The time to compress to JPEG and to compress to RAW should be roughly the same, and it's the smaller part of the process, so it's the file size and I/O speed that are the main factors for the time to save the photo.
An USB connection is generally slower than the memory card, so it's not likely that downloading directly to a PC would be faster.
One thing that could speed up the process would be to get a faster memory card, but that would depend on whether the camera could actually make any use of the faster card. Different cameras and different memory cards gives varying performance, so you would look for testemonials of what other users of your exact camera model experience with different memory cards.

