Not sure if this is the right section, but:

I have a few servers, 2x

* Intel Core 2 Duo
* E7300 @ 2.66ghz
* 2gb RAM
* IIS6
* Windows Server 2k3

1x

* Dual Core AMD Opteron
* Processor 175
* 2.21 mhz
* 540mb RAM
* Windows Server 2k3

The first two are true dedicated servers with one of the UKs leading hosting companies, the AMD is with 1&1 and it's a virtual server. I use the Intel machines for live sites and the AMD server as a development sever, which consequently is pretty full of crap. Old development sites, unused databases etc but which is also being used quite intensively with about 70 websites being activley developed.

What is driving me mad is that sites that we develop on the AMD machine run nice and quick, everything executes quickly and all is good. As soon as we get the sites on the Intel machines everything goes to pot. For example, I have a website we developed in PHP, running off a MySQL database and using a nice jquery script for the drop down menu. On the Intel machine this takes an age to load, the menu is fully expanded whilst doing so, images take ages to appear (they are all being resized on upload, so its not drawing 2mb files or anything). Generally quite painful. The exact same setup on the AMD machine and the site appears quicker than you can blink.

We also have a brochure site, in HTML with PHP includes (no db) which used an animated accordian menu. On the AMD machine it was perfect, on the Intel machine the accordian appears fully expanded with all the sub menus displayed and eventually once done assumes the correct position.

The Itel hosting company say the server is fine, the processor is not even twitching, php application is fine etc etc. They have no idea as to why this may be happening. I thought maybe it was because the PHP versions are slightly different but then why would this affect javascript on sites using basic PHP includes? Same applies to any settings in php.ini

I'm well and truly stumped and i need to fix this before it snowballs into a bigger issue, if anyone can offer any advice it would be much appreciated. Not sure if there are any benchmark tests or scripts to analyse for potential problems...

Sorry for rambling and thank you in advance.