Fastest filter out files with one time use GCI only

cls
$p='E:\gcp'
$t=GCI -path $p  | % { if($_.LastWriteTime -lt (Get-Date).Adddays(-30)){
return $_.FullName}
 }
 echo $t
 echo $t.count
 #-------------------------------------------------------------
 $r=$t  | sls -Pattern ".pdf"
 echo $r.count
 $y=$t  | sls -Pattern "artifact"

 echo $y
 echo $y.count

 $tt=GCI $y
 echo $tt
 echo $tt.count

I try to filter files last 30 days and I understand above filtration, is it right or any better way to manger ? 

I used where and sort desc also include pdf files or include only folder (artifacts) but it take too much time

I have to 1.2TB data filter out