It's still a very minor difference. If you can run Minecraft at 60 fps, and then run a CoD game at 60 fps...
Running higher resolution texture packs only reduces my fps by about 3 or 4 frames. Turning off tree leaves transparency makes a way bigger difference.
Then how come you can run better on mythruna with /trees low... Trees on high I can run without a performance decrease, but /flora low has to be on. Or I get 3-1 FPS. Also I'm having problems with looking at man made buildings... Towers, and towns. It goes down to 10-5 FPS when looking at a tower... There's a problem with seeing player built things, but I don't know what's wrong.
Just for the record:
/trees low uses about 1/3 the triangles as /trees normal. People who are triangle-limited will see a marked improvement.
The trees always use transparent textures even the green spongy ones... it's just the transparent parts are smaller.
/flora low uses about the same triangles but they are not transparent, they do not move, and there is not 3 texture look-ups per pixel... also the flowers go away completely.
When looking at human made stuff you are seeing different materials than normally appear in the natural world, ie: the "textures on screen" doubles, easily. This is why I say that texture switches are one of the more critical things on the slower cards. The best test of this of all is to go find a secluded and deep ocean and go to the bottom. You will only see stone and dirt... if your frame rate is really high then you are "texture switch limited". In other words, the more different textures you have on screen the slower you will run. A texture atlas can fix this problem and I'm 90% sure Minecraft uses a texture atlas. It also reduces object count which can be a good thing for CPU bound systems.
It the tower you are looking at is only stone and dirt then it may be something else can could just be down to triangle count. You can kind of get an idea of what's going on if you enable full stats with F11. It will show triangle/vertex counts, object counts, number of shaders in use, etc..