In my case, changing the number of simultaneous connection didn't have any
effect on the problem.

ARAIR, the W3C suggests that a client restricts itself to a maximum of two
simultaneous persistent connections per server (or proxy), to avoid server
overload or congestion. For dynamic content, I consider 4 simultaneous
connections still polite (yup, I'm server admin myself). Anyway, server
overload usually leads to DOS, not to "gibberish".

Best regards, Klaus