I was just curious as to how much memory use per page load is too much? I know this may vary depending on the resources of the server, so for general purposes let's just compare this to a virtual dedi. setup with 512 MB of memory.

In an app I am writing, without caching the page load is generally around 2 - 3 MB per page load (KohanaPHP framework). Is this too high or will it cause performance issues? I know this is per page load, and in my case I probably won't see several hundred thousand users per day ( prob. more around 2 thousand a day ).

I also understand some caching methods will use more memory but probably less CPU. Anyone have any insight into memory/cpu usage in your projects?

We use Zend Framework which is far heavier than 3mb per load and we have no problems on our servers, we do have a lot of RAM though.

Generally speaking RAM is much cheaper than CPU to upgrade and CPU tends to degrade much quicker than RAM (until you begin to hit the swap file and then your going to have troubles). RAM will be consistent up until you hit swap, whereas CPU usage does not scale anywhere near as well.

Hope that helped.

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