c# - Why PLINQ is giving worse performance then LINQ Query? -

i trying understand plinq. that,i querying database has 102915 products in it.

but shockingly seeing plinq takes 18 secs normal query takes 4 secs. understand, have read article, plinq performs worse usual linq. still, couldn't understand why took many secs.

to remove on head, removed .order(m.sku) in plinq, still gives same result. here, code linq , plinq version.

plinq version

                shootersentities model = new shootersentities();                 var isonline = cbonline.checked;                 var isdeleted = cbdeleted.checked;                  stopwatch s = new stopwatch();                 s.start();                 var p = m in model.products.asparallel()                         ((m.productonline == isonline) || (m.deleted == isdeleted))                           select new { m.sku, m.productcode, m.quantity };                  var list = p.tolist();                 s.stop();                 messagebox.show((s.elapsedmilliseconds / 1000).tostring());                  datagridview1.datasource = list; 

linq version

                    shootersentities model = new shootersentities();                     var isonline = cbonline.checked;                     var isdeleted = cbdeleted.checked;                      stopwatch s = new stopwatch();                     s.start();                   var p = m in model.products                         ((m.productonline == isonline) || (m.deleted == isdeleted))                          select new { m.sku, m.productcode, m.quantity };                  var list = p.tolist();                 s.stop();                 messagebox.show((s.elapsedmilliseconds / 1000).tostring());                  datagridview1.datasource = list; 

probably because linq version translates query sql (which may or may not run in parallell on server) while plinq version needs retrieve database , run filtering , sorting itself.