Under 64-bit version of Windows the PCIScope prior to version 4.00.008 and ACPIScope prior to version 2.00.005 fail on systems with American Megatrends Inc. Bios.

Synopsis:

 PCIScope hangs during detection phase.
ACPIScope during collecting of the BIOS tables information.
Reason: This problem happens due to incorrectly written BIOS.
Solution for
PCIScope:		 If you are using PCIScope prior to version 4.00.008, turn setting 'DetectACPI' Off (0) in [Options] section of  custom.ini file.

If you are using PCIScope 4.00.008 or later, turn setting 'Force_ACPI20' On (1) in [DetectAcpi] section of custom.ini file.
Solution for
ACPIScope:		 There is no solution for ACPIScope prior to version 2.00.005.

If you are using ACPIScope version 2.00.005 or later, turn setting 'Force_ACPI20' On (1) in [Tables] section of custom.ini file.
Hardware:

This problem was reported by customers using following hardware:

  1. ASUS P8B-C/4L Motherboard with American Megatrends Inc. Bios 2305 x64 (08/15/2012)
  2. Pegatron Corporation 2A86 1.04E01 Motherboard with American Megatrends Inc. Bios 6.10 09/16/2010
    (HP Pavilion Elite HPE-580t)
Explanation:

The ACPI Root System Description Pointer (RSDP) on such systems looks as follow:

00: 52 53 44 20 50 54 52 20 - D0 48 50 51 4F 45 4D 00 "RSD PTR .HPQOEM."
10: 00 00 78 CF 24 00 00 00 - 00 01 78 CF 00 00 00 00 "..x.$.....x....."
 20: 94 00 00 00

Or, in decoded form, as follow:

00: 52 53 44 20 50 54 52 20 - Signature         ('RSD PTR')
08: D0                      - Checksum
09: 48 50 51 4F 45 4D       - OEM ID            ('HPQOEM')
0F: 00                      - ACPI Revision     (0)
10: 00 00 78 CF             - RsdtAddress       (0xCF780000)
14: 24 00 00 00             - Length            (0x24)
18: 00 01 78 CF 00 00 00 00 - XsdtAddress       (0xCF780100)
20: 94 00 00 00             - Extended Checksum

According to "Advanced Configuration and Power Interface Specification", Revision 5.0 Errata A, [November 13, 2013], paragraph 5.2.5.3  "RSDP Structure":

The revision of this structure. Larger revision numbers are backward compatible to lower revision numbers.
The ACPI version 1.0 revision number of this table is zero. The current value for this field is 2.

In other words, the American Megatrends Inc. Bios reports the supported revision of ACPI standard as 1.0.
But, the ACPI Standard 1.0 defines RSDP as follow:

Field Byte  Length  Byte    Description
                   Offset

Signature     8      0      “RSD PTR ” (Note that this signature must contain
                             a trailing blank character.)
 Checksum      1      8      The entire Root System Description Pointer structure,
                            including the checksum field,must add to zero to be
                            considered valid.
 OEMID         6      9      An OEM-supplied string that identifies the OEM.
 Reserved      1      15     Must be zero.
 RsdtAddress   4      16     Physical address of the Root System Description Table.

As you can see, the ACPI 1.0 RSDP provides no address of XSDT table used by x64 system. As result our software assumes that pointer to XSDT is NULL.