3
You can do some simple test.
1. create a basic html page and upload to your host, then access the test page, if its slow then its for sure your hosting problem.
2. clear you IE cache (temporary folder) and then load your home page. now go back to your temporary folder and check the file size that get downloaded. smaller the file size, better the performance.
3. if you are not using large database then, MYSQL should not be an issue, but if you are in doubt, then you turn on the xoops debug mode and look at the query execution time for each SQL query(when you load the home page).
I had a similar problem with GoDaddy shared server due to server overload but they fixed it in 2-3 weeks.
Hope it helps.
Good Luck
Deepak