I also tried all four queries and found that query 1 (SELECT COUNT(*)) was marginally faster in the Client Statistics! Possibly its server dependent?
q4 q3 q2 q1
Client Execution Time14:55:2214:54:4514:54:2714:54:05
q4 q3 q2 q1
14:52:1314:51:5214:51:3914:51:23
"Any fool can write code that a computer can understand. Good programmers write code that humans can understand." -- Martin Fowler