my best guess is this will perform better, but it depends on the data;

also it looks like you are pulling from a view(v_MOTS_RELATED_CONTACT_DATA_N), which itself could be pulling in a lot of unused data/columns that might not be needed

myCTE is a placeholder for your real table name, and you might need to tweak the column names, as I removed any whitespace:

/*--Results

ServerNameMOTSEntries

Server Acat

Server Bcat

Server Ccat,dog,mouse

*/

With MyCTE (ServerName,MOTSEntry)

AS

(

SELECT 'Server A','cat' UNION ALL

SELECT 'Server B','cat' UNION ALL

SELECT 'Server C','cat' UNION ALL

SELECT 'Server C','dog' UNION ALL

SELECT 'Server C','mouse'

)

SELECT ServerName,stuff(( SELECT ',' + MOTSEntry

FROM MyCTE s2

WHERE s2.ServerName= s1.ServerName --- must match GROUP BY below

ORDER BY MOTSEntry

FOR XML PATH('')

),1,1,'') as [MOTSEntries]

FROM MyCTE s1

GROUP BY s1.ServerName --- without GROUP BY multiple rows are returned

ORDER BY s1.ServerName