If I analyze with "aoe profiler" the sites of my magento instance, I can see that rendering the .phtml files take the most time.
In example on low budget vps, "add to cart" can take near to 5 seconds, just for the rendering of the cart template.
On a professional vps with raid0 & SSD, it still takes 2,5 seconds.
I can't see details of rendering process, just which .phtml file and how long it took to render/load.
Is there any way to improve the rendering process of magento 1?