SQL server is Running Very Slow

I used this following query for finding out how many connection are connected, it is showing that 70 connections,my ram is 16GB,  but still my sql server is running very slow. how can i increase my sql server speed. or how can i analyses that.I checked  even when no job was running, but still same speed. I'm using store procedures, SQL jobs no inline queries.

SELECT
    DB_NAME(dbid)as DBName,
    COUNT(dbid)as NumberOfConnections,
    loginame as LoginNameFROM
    sys.sysprocessesWHERE
    dbid >0GROUPBY
    dbid, loginame;