Actually it makes the opposite on my radeon;], in native and x2 internal res I have around 20-30fps crawl without this option, while with it it's full speed easily. Only now I saw that it's different at least in latest gsdx with higher res. IE x3 it's like you say and I can get 50fps without it, while 20-30fps with. Soo it highly depends on gpu and internal res used.
Just an edit couse it's a bit of offtop:
I made a bit more of testing, from what I noticed it's the 2D sprites(meaning whole ui + any menu, yeah including the main one) that give me awfull slowdowns without 8 bit textures. Stupid dmg counter is already -10 fps and hp bars and timer even more to begin with, in main menu at x2 I got like 40 fps without 8 bit textures(lag at 2d menu = lol? yeah, but it's true >.>), double with with it;3. I also remember somebody with hd5770 which had similar experiences soo it does apply to more radeons, through I also read an opinion or two before that this option(allow 8 bit textures) is generally much more usefull in AMD gpu's, soo nothing really new.
Strangely with higher upscalling those 2D sprites feel much lighter on my radeon and at x3 or above that option seem to give the opposite(ie main menu x6 with 8 bit 18fps, w/o - 25fps), through at x3 I still get minor slowdowns one way or another anyway soo my choice kind of simple x2 + fxaa and with 8 bit textures otherwise like I say speed is awfull and goes down by any 2D object.
I'm curious what graphical glitch could happen of 8 bit textures still through, couse I helped some guy on yt once that had hd4650m gpu(meaning pretty much same what recoder has) and he could play at full speed with 8bit tex in native without any buggy frameskip;3.
Just an edit couse it's a bit of offtop:
I made a bit more of testing, from what I noticed it's the 2D sprites(meaning whole ui + any menu, yeah including the main one) that give me awfull slowdowns without 8 bit textures. Stupid dmg counter is already -10 fps and hp bars and timer even more to begin with, in main menu at x2 I got like 40 fps without 8 bit textures(lag at 2d menu = lol? yeah, but it's true >.>), double with with it;3. I also remember somebody with hd5770 which had similar experiences soo it does apply to more radeons, through I also read an opinion or two before that this option(allow 8 bit textures) is generally much more usefull in AMD gpu's, soo nothing really new.
Strangely with higher upscalling those 2D sprites feel much lighter on my radeon and at x3 or above that option seem to give the opposite(ie main menu x6 with 8 bit 18fps, w/o - 25fps), through at x3 I still get minor slowdowns one way or another anyway soo my choice kind of simple x2 + fxaa and with 8 bit textures otherwise like I say speed is awfull and goes down by any 2D object.
I'm curious what graphical glitch could happen of 8 bit textures still through, couse I helped some guy on yt once that had hd4650m gpu(meaning pretty much same what recoder has) and he could play at full speed with 8bit tex in native without any buggy frameskip;3.