What's the timing class to be used for VB.Net?

The problem:
Code:
..9..5...
47...2...
.836.4.1.
.15....8.
...3.7...
.2....74.
.4.5.187.
...7...52
...2..1..
is solved pretty quickly. How are you guys doing on other problems like this one:
Code:
.........
9.....1.7
...718...
2........
..5.8...3
..6.49.18
.18......
.6..3..74
...9...3.