What can cause a website to not always load

Roughly about 20% of the time when clicking on links in my website (www.slr-lens.co.uk), the site completely fails to load. I have tried removing and adding all code segments but to no avail... I've also asked the web hosts, but apparently the server is working normally.

Does anyone have any suggestions about what could cause a web page to sometimes not load? E.g. any specific lines in the php.ini? The site uses sessions, and there's quite a lot of mysql action for each page load.

Internet explorer will say: "Internet Explorer can't load this page" Google chrome开发者_运维技巧 will say: This web page is not avialable: Error 324 (net::ERR_EMPTY_RESPONSE): Unknown error. Firefox will sometimes only show a blank page.

Sorry for being so vague but its a really vague problem! Thanks

The answer (or at least a clue) likely lies within your PHP / Apache error logs.

It could be your Apache logs or you just have a bad host. Either way, it seems to load every time here (10+). Have you tried replicating this problem somewhere else?