Texture Problems, sticky non sharp.

Working on a large project including many buildings (60), i have encountered following problems. (i use NovaSim,APFW,and Paintshop pro).The digital immages are all 512x512, 256 colours,256k in size, but even they are taken with excatly same camera, and processed same way, i have major differences in the "way they act" in my scenery.It seems there is a General problem, with all surfaces south oriented, the texture will not load, and you have nearly to drive your plane into the building (pass it) before the do load. Untill then they are completely faded and non sharp. Other textured sides loads at the same time without any problems, but there is quite a difference in when the textures load in general. Right now, i have a "non-pleasant" situation, because even the buildings are VERY beautifull, with incredible crisp facades, my plane "jerks" and i discover to many load drops, making departing and landing very unpleasent, even i have a general very nice FRPs of 24-30 (locked at 30).I remember that Swedflight and some of the proff. designers have had precicely the same problems with general large airports like copenhagen (i an smaller scale) but it seems they have found a way around it through there updates.I will be most thankfull, if anyone can inlighten my way, because it really stall my progress ;o) Thanks in Advance ;o)