Slowness using plugin

I have two instances of wordpress on the same server both are multisites.
One uses subfolders and the other uses subdomains with the dm plugin.

When I visit any site on subdirectory site it is snappy.
When I visit the main blog for the subdomain install it is snappy.

All of my mapped domain sites take 2 or more additional seconds to load. P3 says dm plugin takes 2-3 seconds on mapped sites and .03 seconds on the main blog.

I have no php errors and have turned on debug mode and see nothing.

I checked the queries for the mapped domains and they all make the initial query:
SELECT TOP 1 blog_id FROM sh_domain_mapping WHERE domain = N'news.staging.site.org' ORDER BY LEN(domain) DESC |~|a:1:{i:0;O:8:"stdClass":1:{s:7:"blog_id";s:1:"7";}}|~|

and then there are several queries to find other blogs when none of the other sites are being accessed such as:
SELECT TOP 1 domain FROM sh_domain_mapping WHERE blog_id = '1' AND active = 1 |~|a:0:{}|~|

SELECT TOP 1 domain FROM sh_domain_mapping WHERE blog_id = '6' AND active = 1 |~|a:1:{i:0;O:8:"stdClass":1:{s:6:"domain";s:39:"leader.staging.site.org";}}|~|

that is just a partial list but it has queries like that for several blogs in the network.

This is from clearing the query log and hitting one site in my staging environment 1 time on the homepage.

Any assistance would be greatly appreciated.

http://wordpress.org/plugins/wordpress-mu-domain-mapping/