* Yes i upgraded from SS 2.4
* Check for the server specs [url]http://bit.ly/1kAZeVs[/url]
* In Chrome it seems a bit faster, however it is still not the optimal speed
* The problem remains already when i try to open a link like "home" to edit. The most of the pages exists of Blog posts from the Blog plugin
* There are no problems when running a dev/build (?flush=all)
Thanks for the information, the only bit that could affect the speed from what I can see is the upgrade, which is dependent on what modifications were made during the upgrade. However, in order to get to the bottom of what is going we are going to need more information.
If you have firebug installed, can you go to the administration area, then open Firebug and enable the net panel. Once you have done so can you click on the home link and share the results here. This will give us a fair bit of information on what happens when you click on the link, as depending on the modules you have installed one of many things can be happening and we just need to narrow down what it is.
Could be caused by the fact that this is a very large blog site. Maybe because most entries are in the second level of the SiteTree so that too many pages are preloaded to construct the SiteTree, which wouldn't normally be the case in a typical website?
This must be a known issue, because there is this module: https://github.com/icecaster/silverstripe-largeblog
It handles the blog management in ModelAdmin, that is far better suited to handle large numbers of DataObjects. I've not tested it, but I think it might work, combined with excluding the blogpages from the SiteTree, so that that as well would become manageable again.