SharePoint – Determine the Site Definition used to create a Site Template (.STP)

The performance impact of using Site Templates versus Site Definitions is generally overstated.

Why?

Well, lets take this example:

1. You take a Team Site site definition.
2. You save it as a new Site Template
3. You then create a new sub web based on this new site template.

What have you got? Well, the important thing to remember is that "Ghosting" happens at the PAGE level, NOT at the SITE level. Since you have not customised ANY pages, then any pages you access are still coming directly from the Site Definition, directly from the filesystem.

Want to prove it, here are two tests:

First Test

1. Try modifying the default.aspx page in the original Site Definition.
2. Check your site template, notice you see the modification.
3. Its still "Ghosted" to the filesystem

Second Test

1. Create a new site definition.
2. Create a new site based on this new Site Definition.
3. Create a new Site Template
4. Send the site template to a mate with SharePoint and ask them to create a new subweb based on it.

It will fail. Why? Because the Site Definition does not exist on their machine.

So, to get back to your question, "Are SharePoint site templates really less performant than site definitions?" my answer would be: "Performance considerations should not play a role in your decision to use a Site Definition or a Site Template, the functional objective you have should be". Now it get controversial, but for me, there are very very few reasons to opt for a Site Definition over creating Features.

As far as "Ghosting" goes. Yup, when customised your page will be stored in the Database, and yup, you will have to do a database round trip to get it. But, SharePoint, smart that it is, will of course cache this. So, in theory, yup its slower, in practice, no one really notices.

Ghosting has been in the product since 2003 (probably in STS before that, dont remember) and I have never seen official guidance on the performance impact it has, nor anyone speculating beyond the "it is slower" comments.

This leads me to believe that it just isn't really worrying about. The bigger worry with "Ghosted" pages is the difficulty that comes with maintaining them, but then, with 2007 and Masterpages this is a much smaller problem.

Found here:

Templates created in SharePoint 2007 are not directly usable in SharePoint 2010. In SharePoint 2007 templates are stored as .STP files, in SharePoint 2010 site templates are stored as .WSP files. They are different formats and incompatible with each other.

The only possiblilty would be to create a site with it in a SharePoint 2007 environment and then upgrade that environment to SharePoint 2010. After the upgrade you may be able to create a new template in SharePoint 2010.

MSDN: Import Template in Share Point 2010