Like @FranticFish said, going to WordPress and not optimizing it can be problematic.
I'm assuming your old .asp site was written to do just the minimum necessary to render a page, which would make it reasonably fast. WordPress, on the other hand, does a bunch of operations behind the scene per page load.
Test your page speed here:
[
webpagetest.org...]
You can use this plugin to profile your pages and get an idea of what's happening behind the scenes:
[
wordpress.org...]
If you can, install a caching plugin. I prefer Quick Cache:
[
wordpress.org...]
They have a renamed version called ZenCache, but I don't really know what the difference between them are:
[
wordpress.org...]
I have experience using the prior, so I can only vouch for that.
Whenever I make any changes, I crawl a few key pages and download the rendered HTML output. You can use any crawler, but I prefer this free one:
HTTrack Website Copier
[
httrack.com...]
This gives me a before and after snapshot of the source code, then I use a text comparison application to compare them. This is helpful to point out any accidental omissions or screw ups that might have been committed (e.g., messed up title tags, wrong canonical tags).
Finally, consider installing an SEO plugin, such as:
[
wordpress.org...]
I'd put this last plugin at the top of the list of must-haves on WordPress.