I have some clips with sony nx 5 pal system and rec settings AVCHD FX (24Mbps) 1920x1080/25p and manual speed 50 ,in premiere cs 5.5 what profile can use AVCHD 1080p 25 or AVCHD 1080p 50 for beter results?
Thanks

You have to use the same preset in Premiere and your cam: same resolution (1920x1080), same frames per second (25) and same type of frame recording (progressive [p] or interlaced [i]).
This is the norm.

Also, there are variations:

If you have recorded 50p, then you can edit in 50p or 25p. In 25p you have half speed slow motion without any render or generating false frames: it's native. If you edit in 50p, you don't have any extra option.

If you have recorded 25p, 50p timeline is useless (IMHO).

If you have recorded 50i, you can use 50i or 25p timeline, but it's better to use 50i and render the final clip in 50i or 25p (desinterlaced).

Remember that "all" new TVs (flat tvs, LCD, Plasma, LED) "converts" interlaced material to progressive automatically and in real time.

By "manual speed" you mean "shutter speed", right?
There is no reason to choose 50p if you recorded in 25p.

yes i mean "shutter speed" i have in camera select AVCHD FX (24Mbps) 1920x1080/25p and shutter speed 50 in premiere cs 5.5 what profile can use AVCHD 1080p 25 or AVCHD 1080p 50---OR
i have in camera select AVCHD FX (24Mbps) 1920x1080/25p and shutter speed 25 in premiere cs 5.5 what profile can use AVCHD 1080p 25 or AVCHD 1080p 50 whats is beter? What is the most appropriate of these 2?