This is typical for an underpowered system. Your components are not bad, they should be able to handle AVCHD easily, if the system is properly tuned. What complicates matters is your source material from the Sanyo Xacti, which is difficult to edit and the fact that you cripple your system by using QuiRckTime, which effectively cripples an otherwise nice 64 bit system to run in 32 bit mode.
Unless you are on a MAC, never use QuiRckTime if you can avoid it.
Thanks for answer but,
well I was just doing the same with the same config except the SSD so I think it's not a problem of power ?
(I am just reading in premiere the file, nothing else)
Try changing your playback resolution to full resolution so your CPU does not get bogged down scaling the resolution.
Playback was on 1/2 => on full NO PROBLEM ANY MORE
Thanks a lot !