   DirectDraw app videomem corruption
  An old directdraw app that I created a couple of years ago has started having problems on some modern video cards. Cards I know of causing problems are Gforce4 and S3 Pro Savage DDR. The surfaces are loaded to videomem (or sysmem if video is full). After rebuilding the app and sending everything to sysmem it''s fine so something is going on with video memory. I have updated drivers and this doesn''t help. I''m a bit out ''of the loop'' with directx so any ideas would be appreciated. The dimensions of the surfaces affected varies greatly. Some are fairly large (up to 5104 x 60) (16bit).Cheers. 
  You cannot store images WIDER than the current screen resolution in video memory.  It TENDS to work for a while, but as you have noted, it eventually messes up.Either cut these images up, or store them in RAM instead and take the hit when blitting. ;  Thanks Andy - I remember reading somthing like that a long time ago but thought it was related to a few old video cards only. Is there a restriction on the HEIGHT of the surface or is it just the WIDTH?Cheers. ;  Just the width, and AFAIK it is all video cards that denote this as "unspecified behaviour"/ 