Very slow backup to Mac (mac only)

I read through a lot of other threads on this topic, but most of the responses seem to be related to Windows computers.

My iPad always backed up and synched fine. Recently, I have been doing work with digital magazine publishing, so I downloaded the Wired Magazine application and a few issues. I also purchased a few other digital magazines. I need to look into this for my job.

I'm not sure when, but suddenly I could leave the iPad connected for hours on end in "Backing up ipad" and I'll always need to cancel it, since I eventually need to use the **** thing, or leave for work.

I also have an iPhone 4, and that backs up in seconds, even though there are many more gigs of apps, music, and photos on the phone than the iPad (which has 1.85 gb of apps and no music or photos).

I am using the new cable, the same cable, computer, and usb port as the phone but only the phone backs up successfully. This is getting quite ridiculous.

Have any other Mac 10.6 users run into this, and have you solved anything? The various threads about deleting apps to find a "bad app" are silly; all the apps on there I need, and data is data. If the phone can back up over 4 gb in 30 seconds, the iPad should be able to back up less than half that in less than 24 hours, no?