"Importing images is an aspect of Lightroom that users have always found wanting. Beta 4 improves things a bit but probably still has some ways to go before it's nearly as slick as the competition. That said, the changes that have been implemented are to be welcomed. For example, you can

now choose to use the preview embedded within the image (i.e. Use Embedded and Sidecar Previews) or previews rendered directly form the RAW images during import (i.e. Render Standard Previews). There is another preview option, but it's currently only available after import (i.e. 1:1 Previews). This last preview type is rendered using the default sharpen and denoise settings, so takes a while longer to create if done in a batch (Library module: Library>Render 1:1 Previews). If you've already imported images using either of the two options found within the import dialog then simply zooming into an image (press "Spacebar") is enough to create the 1:1 preview. Anyway, whatever preview type you choose to use you should find that import and preview generation in Beta 4 is significantly faster than in previous betas. By way of example, using my Apple Dual 2.5GHz G5 I imported 6000+ Canon EOS 1DMKII images in 2 hours 20 minutes using "Standard Preview"; the same process took in excess of 17 hours with Beta 3. Using the embedded preview option it took less than 35 minutes. Obviously, lower powered computers than mine will take longer, but should still be a lot faster than earlier betas."