The RAM thing is a nice theory until you consider the 4th gen iPod touch has a similar number of pixels as iPad 1 4th generation iPod touch is 960 x 640 = 614,

The RAM thing is a nice theory until you consider the 4th gen iPod touch has a similar number of pixels as iPad 1 4th generation iPod touch is 960 x 640 = 614,400 1st generation iPad is 1024 × 768 = 786,432 Those extra 172,032 pixels could have been enough to prevent something from performing adequately.