Harry is correct. Look at the specs and do the calculations and you will see that the 350 screen has 200 dpi both vertically and horizontally whereas the 650 only has 166 dpi vertically and 168 dpi horizontally.

However, the 350 screen is 3" x 4" and the 650 screen is 3.57" x 4.82". Another way to state that is that the 600 pixels on the 350 are 0.84 times the size of the 600 pixels on the 650 and the 800 pixels on the 350 are 0.83 times the size of the 800 pixels on the 650. So what your eye sees on the 350 and the 650 if both show the same amount of text (same number of words per line and same number of lines) are actually roughly equal in resolution. How can that be? Simple. Assume the same amount of text on both screens but the text has to be smaller on the 350 because the screen is physically smaller. So 200 dpi on the 350 across the 600 pixel side times 0.84 smaller size of screen (compared to 650) and the result is what appears to your eyes as 168 dpi, the same as the 650. Do the same math for the 800 pixel side of the 350 and it too now appears to match the 650 at 166 dpi.

So what the heck does this mean? It means if you show the same exact amount of text on the 350 as on the 650, they will appear to have the same resolution. If you increase the font size on the 350 where it is the exact same physical size as the text on the 650, less text will fit on the 350 screen but your eyes will appear to see a higher resolution per word.