diff --git a/src/video/dedicated_v.cpp b/src/video/dedicated_v.cpp
--- a/src/video/dedicated_v.cpp
+++ b/src/video/dedicated_v.cpp
@@ -135,6 +135,8 @@ static FVideoDriver_Dedicated iFVideoDri
 
 const char *VideoDriver_Dedicated::Start(const StringList &parm)
 {
+	this->UpdateAutoResolution();
+
 	int bpp = BlitterFactory::GetCurrentBlitter()->GetScreenDepth();
 	_dedicated_video_mem = (bpp == 0) ? nullptr : MallocT<byte>(_cur_resolution.width * _cur_resolution.height * (bpp / 8));