SQL Load Fact with Merge Statement Slow - sql

Question

I'm loading a fact table using MERGE and it's taking 44 minutes for 1 million records. Is there a way I can improve this?
My query:
MERGE INTO dbo.FactProjMarketCode AS target
USING (
SELECT
SourceSystem = 'ORACLE_ERP',
ProjMarketCodeSourceId = jmc.XT_JOB_MARKETING_CODE_ID,
p.ProjectId,
MarketCodeId = ISNULL(mc.MarketingCodeId,-1),
Weight = 0.01 * ISNULL(jmc.WEIGHT,100),
WasMissing = CASE WHEN jmc.WEIGHT IS NULL THEN 1 ELSE 0 END,
jmc.LAST_UPDATE_DATE
FROM
dimProject p
LEFT JOIN stage.XT_JOB_MARKETING_CODE jmc
ON p.ProjectSourceId = jmc.XT_PROJECT_ID
LEFT JOIN DimMarketingCode mc
ON jmc.MARKETING_CODE = mc.MarketingCode -- should create column MarketingCodeSourceId
AND mc.SourceSystem = 'ORACLE_ERP'
WHERE
p.SourceSystem = 'ORACLE_ERP'
) AS source
ON target.SourceSystem = source.SourceSystem
AND target.ProjMarketCodeSourceId = source.ProjMarketCodeSourceId
WHEN MATCHED AND source.LAST_UPDATE_DATE > target.LAST_UPDATE_DATE
THEN UPDATE SET
target.ProjectId = source.ProjectId,
target.MarketCodeId = source.MarketCodeId,
target.Weight = source.WEIGHT,
target.WasMissing = source.WasMissing,
target.LAST_UPDATE_DATE = source.LAST_UPDATE_DATE
WHEN NOT MATCHED BY target
THEN INSERT (
SourceSystem,
ProjMarketCodeSourceId,
ProjectId,
MarketCodeId,
Weight,
WasMissing,
LAST_UPDATE_DATE
) VALUES (
source.SourceSystem,
source.ProjMarketCodeSourceId,
source.ProjectId,
source.MarketCodeId,
source.Weight,
source.WasMissing,
source.LAST_UPDATE_DATE
)
WHEN NOT MATCHED BY source
THEN DELETE;