Dual Link DVI can do as much as it can fit in 9.9 gbit/s with 8:10 encoding , meaning only 80% can actually be used for data. So in essence, you have 7.92 gbit per second for your data. or 7920 megabit per second or (since we have 8 bits in a byte) 990 MB/s
1440p is 2560x1440 pixels, so using 3 bytes per pixel (red, green,blue) you're looking at 2560x1440x3 = 11,059,200 bytes or 10800 KB or 10.54 MB/s
So how many times can we send 10.54 MB in a second when the maximum possible is 990 MB in a second? Simple, 990 / 10.54 = 93.92 fps.
So according to our math, 93 fps would be the theoretical limit but there's some data besides the raw pixels sent on the cable when talking to the display processor in the monitor, so let's just round it down to be safe and say 90 fps may be duable, but I would be more comfortable saying 85 fps.