Hello all.
First of all, I would like to wish everybody a happy new year, and this year every single one of you to make some steps closer to his dreams!

Now, to the point. I just upgraded my system to 05.06.00 edition, from the 05.04.02 I was before. First of all, I encountered this error, where I had to make the change in DefaultAppPool in order to continue with the proccess. After that, the upgrade went smooth, and seems to work fine, exept one major problem...

Even after restarting the whole machine, and not just the IIS, the site is terrible slow. It takes 20-30" to load the home page which consists of a banner and a Text/Html module... Even logging out takes almost a minute!

Can anybody help? I need to upgrade our website to the new version, however I cannot risk it while the response is so slow.

Thank you Sebastian, you are always here :)

However, yes I read your post, and I was aware before the upgrade since I have done this before.
The problem started heavily just after the upgrade. Before that the site was realy fast after every upgrade from 5.0 to 5.04.02.

No, just a single language. Actually we are using en-GB as default and en-US is disabled.
We currently use very few modules (text/html, banners) and 9 of our own that are very light and use only basic functionality of DNN.
There is no proccess that uses cpu/mem/IO at the time. While requesting another page in DNN, sql proccess uses up to 22% of cpu and w3wp process reaches 14%. SQL is on a different server. IO is also low during requests.