Firstly, DNN is an awesome platform, and the latest 4.5.1 is also great! Being one of those development houses that waited in anticipation for the 4.5.0 and now 4.5.1 upgrade, we couldn't stop ourselves from upgrading as soon as it was released.

Now, a major issue has arisen. The inclusion of AJAX by default adds an extra 60 - 100 KB's to page sizes! I am not an AJAX guru, so I will first tread carefully and ask confirmation on this claim? An easy way to determine this is by installing/using Mozilla Firefox and then installing an add-on called Firebug; a real brilliant tool that shows what gets downloaded on each page load (Open Tools->Open Firebug on Firefox main menu. Then select the Net tab and start loading pages).

The webresource.axd and scriptresource.axd created as result of AJAX ads a huge overhead to each page load. Now the jackpot question is, can this be disabled selectively on pages that don't use any AJAX, or at least be disabled completely?

Many improvements have been made in making DNN it more performant, but if the core is faster, does it really matter if you don't have a high speed connection and page sizes has increased so dramatically?

He's talking about the extra GETS to ScriptResource.axd, not the size of the html in the page.

Compression or whitespace filter won't help because they break the Javascript.

It would be nice if ajax could be disabled in page settings. 
I didn't think it was supposed to add the script manager unless there was an Ajax module on the page, but I just created a page with no modules and it had two GETS to ScriptResource.axd.

John yeah I missed the point on that one regarding the linked files.  I did a quick check on my page and I only have 23k in added script files for the AJAX functionality on my site, which in my opinion isn't all that bad.

I wonder why my script size is so much smaller then the above mentioend sizes....