We have a number of 32-bit Windows 2008 print servers that we want to migrate to Windows Server 2012, for the printer management PowerShell cmdlets, among other things. I found a helpful blog post about using the PRINTBRM utility to migrate print queues, which mentions that you need to have both 32-bit and 64-bit drivers versions of all the drivers in order to migrate from a 32-bit to a 64-bit OS instance.

I wrote a little script to quickly show me which print drivers need a 64-bit version installed. It can take a moment to run if you have many printers configured.

<#
.SYNOPSIS
Lists printer drivers,  whether 32- and 64-bit versions are installed,
and how many printers are using each driver.

.EXAMPLE
PS C:\local\scripts> .\Get-PrinterDriverArchitecture.ps1 | format-table -auto

Name                                       x86   x64 Printers
----                                       ---   --- --------
Brother HL-5250DN                         True False        5
Brother HL-6050D/DN                       True False
Brother MFC-8890DW Printer                True False
Brother PT-18R                            True False
Epson LQ-570+ ESC/P 2                     True False
HP Business Inkjet 2230/2280              True False        1
HP Business Inkjet 2250 (PCL5C)           True  True
HP Business Inkjet 2800 PCL 5             True False        1


.EXAMPLE
PS C:\local\scripts> .\Get-PrinterDriverArchitecture.ps1 | where x64 -eq $false | ft -a

Name                                      x86   x64 Printers
----                                      ---   --- --------
Brother HL-5250DN                        True False        5
Brother HL-6050D/DN                      True False
Brother MFC-8890DW Printer               True False
Brother PT-18R                           True False
Epson LQ-570+ ESC/P 2                    True False
HP Business Inkjet 2230/2280             True False        1
HP Business Inkjet 2800 PCL 5            True False        1
HP Business Inkjet 3000 PCL 5            True False


.NOTES
 - Author: Geoffrey.Duke@uvm.edu
 - Date  : May 23, 2013
#>

$wmi_drivers = get-wmiobject Win32_PrinterDriver -Property Name
$drivers = @{}
foreach ($driver in $wmi_drivers) {
    # Isolate the driver name and platform
    $name,$null,$platform = $driver.Name -split ','

    if ( -not $drivers[$name] ) {
        switch ( $platform ) {
            'Windows NT x86' { $drivers[$name] = [ordered]@{ 
                                 'Name'=$name; 'x86'=$true; 'x64'=$false }; break }
            'Windows x64'    { $drivers[$name] = [ordered]@{ 
                                 'Name'=$name; 'x86'=$false; 'x64'=$true }; break }
             default         { write-warning "Unexpect platform $platform on driver $name"}
        }
    }
    else {
        switch ( $platform ) {
            'Windows x64'    { $drivers[$name]['x64'] = $true; break }
            'Windows NT x86' { $drivers[$name]['x86'] = $true; break }
             default         { write-warning "Unexpect platform $platform on driver $name"}
        }
    }
}

# Add a count of the number of printers using each driver
get-wmiobject Win32_Printer -Property DriverName | 
    foreach { $drivers[$_.DriverName]['Printers']++ }

# Output collection of objects
$drivers.keys | sort | foreach { New-Object PSObject -Property $drivers[$_] } 

I hope this is useful to others.