No matter what CMS you use, Drupal or WordPress, there is a need to make your site run fast and efficiently. While there are lots of tools out there supporting only one platform or the other, I want to make a suggestion for using the same tool: Varnish.
The Need: Serve Anonymous Users
For the vast majority of websites, the main focus with website performance is supporting the traffic of anonymous users. While it is less difficult to support anonymous users than it is to support logged-in (authenticated) users, there are often more of them using your site at any given time.
This means the need to provide adequate performance for any platform, WordPress or Drupal, still exists. While each platform was built for a specific use case, you don't need to look for platform-specific tools to solve the problem.
This platform was intended to be ready instantly after install and is ripe for the average non-technical user. Most of the needs, like performance, are already taken care of moderately well. While there is room for improvement and there are plug-ins available, most users often don't need the extra boost.
Easy Performance. WordPress is simple and starts out pretty fast out of the box. Because the average user is a non-technical blogger needing a tool to communicate, they don't often need more performance beyond what's already offered. This means that the options to build upon the current performance are not as plentiful, given the low demand.
Fewer Scalability Options. For the same reason as stated above, the average user on the WordPress platform isn't looking to grow their website like a large enterprise would. Because the needs of the community don't lean toward the high end of scalability, there aren't as many tools available.
This platform was built with large-scale companies and enterprise needs in mind. It was designed with low performance or other advanced features because the average user will build upon the core software with their own modules and APIs. Drupal was designed with basic functionality that can easily be added to and built upon.
Many Performance Options. These options are designed to allow capable and skilled developers customize them as needed. The enterprise-sized need of this platform means there is high demand for performance tools, and thus there is a readily available supply.
Geared Toward Scalability. Again, the need of the platform is to provide a highly customizable web solution for large companies. Users start with this platform or move to it because they want a solution that grows with them. Drupal will scale along with your business goals.
The Right Tool: Varnish
While most WordPress users usually aren't looking for this boost, it is available and completely possible to implement it. For Drupal users, this is the ideal choice for scalability at the enterprise level. Varnish serves cached content to anonymous users quickly which provides the needed boost in performance websites are want. It scales easily so you can do all the marketing you want and know that Varnish has your website's back.
Photo by Mann-ist-O