http://ayende.comAyende @ RahienCopyright (C) Ayende Rahien 2004 - 2021 (c) 202660Phil, The SamAccountName isn't really helping perf in any material way. And the GetAuthorizationGroups() is used to get all groups in the hierarchy.http://ayende.com/158401/are-you-an-administrator#comment4http://ayende.com/158401/are-you-an-administrator#comment4Fri, 14 Sep 2012 07:47:06 GMT<s>whatever</s> whether Just sayin' ... http://ayende.com/158401/are-you-an-administrator#comment3http://ayende.com/158401/are-you-an-administrator#comment3Wed, 12 Sep 2012 21:36:37 GMTi suppose your solution will have something to do with the current name of the method, "IsAdministratorNoCache" and in particular that "NO CACHE" part ;)http://ayende.com/158401/are-you-an-administrator#comment2http://ayende.com/158401/are-you-an-administrator#comment2Wed, 12 Sep 2012 12:59:46 GMT You could help the API by telling it you are providing a SamAccountName. var up = UserPrincipal.FindByIdentity(ctx, IdentityType.SamAccountName, username); Not really sure the difference between GetAuthorizationGroups and GetGroups, but, you could just call using (PrincipalSearchResult<Principal> groups = up.GetGroups()) { return groups.Any(principal => principal.Sid.IsWellKnown(WellKnownSidType.BuiltinAdministratorsSid) || principal.Sid.IsWellKnown(WellKnownSidType.AccountDomainAdminsSid) || principal.Sid.IsWellKnown(WellKnownSidType.AccountAdministratorSid) || principal.Sid.IsWellKnown(WellKnownSidType.AccountEnterpriseAdminsSid)); } Look forward to seeing your analysis of what took all the time, http://ayende.com/158401/are-you-an-administrator#comment1http://ayende.com/158401/are-you-an-administrator#comment1Wed, 12 Sep 2012 09:54:30 GMT