I have seen some posts in the net, that +agi ring is better for ret pally than +str one...
anyone knows about it?

Maybe the posts are pre-patch where there wasnt any str dps rings, there used to be only that agi one. Sounds weird to weight agi over str for pallys, dunno tho. Cant say i've done much whacking as retri. Any.

i think i saw somewhere that agi trink gives approximately 1% more dmg than str one.
After some more research:
Most of very well geared pallys that got it, the agility ring....

http://www.wowarmory.com/character-shee ... n=Adeleigh

here is one that did 11.6k dps on festergut....
http://eu.wowarmory.com/character-sheet ... Majorpayne
and dmg meter:
http://www.wowmeteronline.com/combat/de ... #damageout

I dont see anything too special, 5.7k ap, 40% crit and 4set....
he does have 17% haste,
Could all these together make the 4k dps difference? (i had 7.7k on festergut)

ahh he has shadowmourne

This guy is from my shamans guild.. and he got 2 agi rings he is doing 12k on festergut.
http://eu.wowarmory.com/character-sheet ... Sveticovek