Rackspace and Liquidweb provide decent cloud infrastructure with load balancers. It's easy to attach ad server nodes on demand. Your high CPU usage is a completely separate issue though.
You can link both image and headline using the legacy Direct Selection method like so:
<a href='http://bestadserver.com/www/delivery/ck.php?bannerid={bannerid}' target='_blank'><h3>{headline}</h3></a>
<a href='http://bestadserver.com/www/delivery/ck.php?bannerid={bannerid}' target='_blank'><img src="{yourimage}"/></a>
And you can even add a pixel into the body of the article to track opens/views.
<img src='http://bestadserver.com/www/delivery/avw.php?bannerid={bannerid}&cb={random_number}' border='0' alt='' />
You can use the legacy Direct Selection method to either call your banners individually, or place them within a single campaign and call that campaigns instead.
More on Direct Selection: http://blackriver.to/2014/01/openx-source-revive-adserver-direct-selection/
Third Party Clicks Tags: http://blackriver.to/2014/01/openx-source-revive-adserver-party-click-tracking/
Click URL and other macros: http://blackriver.to/2014/01/openx-source-revive-adserver-magic-macros/
Revive Adserver is a fork of OpenX Source. OpenX Source is no longer developed. Essentially, for your purposes, they are the same. Switch over now and never look back!
You can set it to any value (in seconds), it's located on Configuration Panel -> Banner Delivery Settings. You can also find the same value in the Revive config file.