d3wp

This plugin shows Google PageSpeed scores for the themes installed from the official WordPress theme repository. 
With this you can easily determine which themes are fast and which ones can slow down your WordPress blog when used.
Plugin shows 2 scores (see screenshot):
<ul>
<li>Google PageSpeed score for blogs’ Home page</li>
<li>Google PageSpeed score for blogs’ sample Post page</li>
</ul>
More than 2600 themes were tested lately.
Every theme was tested on a fresh WordPress installed instance populated with a sample content. 
No additional plugins were installed to avoid any unwanted impact on the speed test.
NOTE: 
This plugin calls <a href="http://www.wpspeedster.com" rel="nofollow ugc">wpspeedster.com</a> API to obtain necessary information about PageSpeed scores. 
Only theme slugs are send to the API, no additional or personal information is send.

Themes Speed Test

This plugin shows Google PageSpeed scores for the themes installed from the official Wordpress theme repository.

aabweber

This plugin allows you to place a widget for internet connection speed test. 
If your theme doesn’t support widgets you can insert directly to your theme code something like that:
<pre><code><?php showSpeedTestHTML();?>
</code></pre>
or
<pre><code><?php echo getSpeedTestHTML();?>
</code></pre>
See installation section to learn how to change widget template.
<h3>Arbitrary section</h3>
<h3>A brief Markdown Example</h3>

Internet Connection Test

This plugin allows your users to test internet connection speed.

Themes Speed Test vs Internet Connection Test