very bad fcgi performance

[nils]

All CPUs stay idle during almost the whole request
It's like this:

Code:

top - 23:20:49 up  6:39,  1 user,  load average: 0.05, 0.05, 0.01
Tasks: 152 total,   1 running, 150 sleeping,   0 stopped,   1 zombie
Cpu(s):  0.1%us,  0.1%sy,  0.0%ni, 99.8%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   1048576k total,   278324k used,   770252k free,        0k buffers
Swap:        0k total,        0k used,        0k free,        0k cached

A Request takes place as after the following pattern:
- Browser-GET
- ~1 sec pause
- php-cgi5 uses ~5%cpu for ~1 sec
- ~10 sec pause
- Delivery