Although it's too late now, just thought I would mention since nobody else did, when buying a GPU, lower last digits usually mean low grade GPU.
Example being X10 VS X60
the 10 will always be a low grade GPU, regardless of the first digit.
If you go from a 240, you will want to get something like an X60, otherwise you can expect similar performance from the GPU, regardless of ram amount.
The lower digit GPU's always have lower clock speeds and fewer stream processors/Cuda cores.
Something I learned over the years.
Maybe this information will help someone else someday.