How do I increase size of Terminal on Linux

You can reduce your font size in putty to fit more lines. Using putty, I can see 64-cores in top on a 1920x1200 laptop monitor. You can also look into another way of looking at individual processor statistics.

Is it absolutely essential to see each CPU core's statistics? You could try mpstat -P ALL (installed as part of the sysstat package).

I had to change rows to 60 under Windows option and set "When window is resized:" option to "Change the size of font" to get it to work

A simple solution might be using xterm, which by default uses small font. This way, I can observe 64 cores at 1080 vertical resolution.