My Portable Hard Drives are slow......whats the alternative?

Hi There

I currently have about 1.5TB of photos on 2 external WD hard drives. I run many lightroom catalogues that pull from these drives. The processing/loading speed is becoming very slow and I'm wondering what other options are available.

To be honest I struggle with the process of organizing my photos, I'm not fully confident in the way lightroom handles my files. All I know is that I have everything saved in RAW files on my external drives and lightroom seems to pick up these and runs them on my laptop. But it's becoming pretty slow.

Any suggestions/pointers appreciated.

I have CS5.5 full version with lightroom 3.

Thanks

Sam