cpu overload

Did you tried to look at that SQL 2014 - Performance Dashboard Report as that could tell right away what/where the problem is? You could use the 2012 version of them as described at link below as there were added by default to SQL 2016 and up if I'm not mistaken.

https://www.sqlshack.com/performance-dashboard-reports-sql-server-2014/

In addition to that the scripts below should help identify which DB(s) are using most of the CPU and IO

WITH CPU_Per_Db
AS
(SELECT 
 dmpa.DatabaseID
 , DB_Name(dmpa.DatabaseID) AS [Database]
 , SUM(dmqs.total_worker_time) AS CPUTimeAsMS
 FROM sys.dm_exec_query_stats dmqs 
 CROSS APPLY 
 (SELECT 
 CONVERT(INT, value) AS [DatabaseID] 
 FROM sys.dm_exec_plan_attributes(dmqs.plan_handle)
 WHERE attribute = N'dbid') dmpa
 GROUP BY dmpa.DatabaseID)
 
 SELECT 
 [Database] 
 ,[CPUTimeAsMS] 
 ,CAST([CPUTimeAsMS] * 1.0 / SUM([CPUTimeAsMS]) OVER() * 100.0 AS DECIMAL(5, 2)) AS [CPUTimeAs{96f5cbaad583fb885ff5d18ecce5734bf1e8596949521e20c290401929518f75}]
 FROM CPU_Per_Db
 ORDER BY [CPUTimeAsMS] DESC;

--chck IO per DB
WITH IO_Per_DB
AS
(SELECT 
  DB_NAME(database_id) AS Db
  , CONVERT(DECIMAL(12,2), SUM(num_of_bytes_read + num_of_bytes_written) / 1024 / 1024) AS TotalMb
 FROM sys.dm_io_virtual_file_stats(NULL, NULL) dmivfs
 GROUP BY database_id)

 SELECT 
    Db
    ,TotalMb
    ,CAST(TotalMb / SUM(TotalMb) OVER() * 100 AS DECIMAL(5,2)) AS [I/O]
FROM IO_Per_DB
ORDER BY [I/O] DESC;

Select allOpen in new window

Thank you for the script CPU Time 99% and IO 50%
How to resolve please ?

Best regards