This explanation sounds plausible so I downgraded to GD 1.8.1 and built with that. Sadly there seems to be no speed difference. Still very sluggish.

I think some of it might be my fault... I'm attempting to recreate the Empeg player's small font (like the one used on the track details screen) because it's a nice small font and I need to get a lot of text on the screen. So I painstakingly created the font, converted it to the GD image format, and I have it do a gdImageCopy of each letter into the string I want to display. I am SURE this is inefficient but I couldn't think of a better way to do it. I thought of making a GD font for it, but GD fonts are only in one "color" so the shaded parts of the letters wouldn't work properly.

But even without my custom text routine, things looked pretty slow. So I'll look into some other options. GD 1.8.1 doesn't seem to make a difference. Thanks for the suggestion though.