ConvertFrom-JSON high memory consumption #7698

$JSON = @"
{
  "configGlossary:installationAt": "Philadelphia, PA",
  "configGlossary:adminEmail": "[email protected]",
  "configGlossary:poweredBy": "Cofax",
  "configGlossary:poweredByIcon": "\/images\/cofax.gif",
  "configGlossary:staticPath": "\/content\/static",
  "templateProcessorClass": "org.cofax.WysiwygTemplate",
  "templateLoaderClass": "org.cofax.FilesTemplateLoader",
  "templatePath": "templates",
  "templateOverridePath": "",
  "defaultListTemplate": "listTemplate.htm",
  "defaultFileTemplate": "articleTemplate.htm",
  "useJSP": false,
  "jspListTemplate": "listTemplate.jsp",
  "jspFileTemplate": "articleTemplate.jsp",
  "cachePackageTagsTrack": 200,
  "cachePackageTagsStore": 200,
  "cachePackageTagsRefresh": 60,
  "cacheTemplatesTrack": 100,
  "cacheTemplatesStore": 50,
  "cacheTemplatesRefresh": 15,
  "cachePagesTrack": 200,
  "cachePagesStore": 100,
  "cachePagesRefresh": 10,
  "cachePagesDirtyRead": 10,
  "searchEngineListTemplate": "forSearchEnginesList.htm",
  "searchEngineFileTemplate": "forSearchEngines.htm",
  "searchEngineRobotsDb": "WEB-INF\/robots.db",
  "useDataStore": true,
  "dataStoreClass": "org.cofax.SqlDataStore",
  "redirectionClass": "org.cofax.SqlRedirection",
  "dataStoreName": "cofax",
  "dataStoreDriver": "com.microsoft.jdbc.sqlserver.SQLServerDriver",
  "dataStoreUrl": "jdbc:microsoft:sqlserver:\/\/LOCALHOST:1433;DatabaseName=goon",
  "dataStoreUser": "sa",
  "dataStorePassword": "dataStoreTestQuery",
  "dataStoreTestQuery": "SET NOCOUNT ON;select test='test';",
  "dataStoreLogFile": "\/usr\/local\/tomcat\/logs\/datastore.log",
  "dataStoreInitConns": 10,
  "dataStoreMaxConns": 100,
  "dataStoreConnUsageLimit": 100,
  "dataStoreLogLevel": "debug",
  "maxUrlLength": 500
}
"@

$Count = 39999
$jsonarr = "[" + (($json + ",") * $Count) + $json + "]"
[system.gc]::Collect()
write-host ""
write-host ""
write-host "JSON -- Objects: $($Count + 1)"
write-host "JSON -- Length:  $($jsonarr.length / 1024 / 1024 ) Megabytes"

$BeforeMemory = $((get-process -pid $PID).WorkingSet)
[void] (convertfrom-json $jsonarr)
$AfterMemory = $((get-process -pid $PID).WorkingSet)

$MemoryDiff = $AfterMemory - $BeforeMemory

write-host "Memory Usage -- Before:     $($BeforeMemory  / 1024 / 1024) Megabytes"
write-host "Memory Usage -- After:      $($AfterMemory  / 1024 / 1024) Megabytes"
write-host "Memory Usage -- Difference: $($MemoryDiff  / 1024 / 1024) Megabytes"
write-host "Memory Usage -- Multiple:   $($MemoryDiff / $jsonarr.length)"

Name                           Value
----                           -----
PSVersion                      6.1.0-preview.3
PSEdition                      Core
GitCommitId                    v6.1.0-preview.3
OS                             Microsoft Windows 10.0.17134
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0