I use..
- MCPatcher and have never had this kind of problem in my life. It's either a texture pack issue, a video card issue, or your trying to load multiple incompatible mods together such as MCPatcher/Forge.
Forge has been a fickle bitch for me and I've tried to use it before. I deleted everything, ran Forge by itself and I spent maybe an hour trying to install a mod so simple as "Single Player Commands" and "Toomanyitems", neither worked for me. Then I tried to install Custom NPC's after installing those two mods (an hour later) and all three said they were loaded, but refused to actually work within the game itself. So I finally dug through about ten tutorials, got it all to work, decided it was way too much work for not that big of an improvement, and dumped it all for MCPatcher because it has something so simple that no one else has - connected textures. Oh and it has a friendly interface that makes shit much easier and quicker.
- Optifine, its a graphical tweaker. Its designed to make vanilla minecraft run smoother not look better haha. I used it before but now it doesn't work nearly as well for me. So I once again dumped it in favor of MCPatcher.
So to answer the original question - its either Forge, your Texture Pack, Video Card or conflicting mods. MCPatcher (though everyone hates it) is actually not so much of a problem as long as you aren't installing mods that require heavy modifications such as a pack that adds many new blocks (which most blocks/weapons aren't really worth adding as most look like crap or do very little).