startup takes a while on the older pi's due to a number of factors. Some of the biggest things are:

• SD Card: make sure that you have a fast sd card (or set up symbolic links to a fast thumb drive). There are a lot of read operations on startup due to theming and asthetics
• Processing Power: If you have a good power supply, I fully recommend overclocking. I've had mine overclocked for 2 years with no heat sinks or active cooling measures. Still runs great.
• Memory split: This depends on what kinds of games you play. If you are running mostly older mame or nes games, you can get away with 64mb. I usually have mine set at 128mb though.

There are still some optimizations that we can do on our end (one of the biggest things that I'd like to do is to get all of a themes images condensed into one image, there's a lot of load time added when there are lots of files that need to be opened.) But I probably won't work on that until I have time to revamp the theme system. I'd like to make a drag and drop system on the web frontend.

The problem is that there is a lot of config/database files that have to get read into the system before it can display the current theme + rom list. I moved my piplay folders to a fast usb thumbdrive and then just created symlinks. My load times are pretty negligible after doing that.