We have a WordPress website that was moved from shared hosting to VPS and now it is loading slowly. We spoke to the web hosting support and they told us that the reason the site is slow now is as follows:
"Regarding the slowness, it looks like it's caused by the fact, that PHP is running as CGI, which causes high disk io during every single request to every single page on your site. Please try to switch PHP to run as Apache module or rebuild PHP with FastCGI support."
We need someone who understands the needs to resolve this issue, and has a knowledge of WordPress and MySQL databases, to perform the needed and help our website to once again load much faster.