Shuttle SS59G V2 Pentium D Support Questions

Just got a SS59GV2 and Pentium D 945. (the guy who sold me the Shuttle said it would work) Systems runs fine with Windows XP and regular activities. However, when it comes to intense calculations running programs like Super Pi or Quickpar, it's very unstable. Contacted Shuttle, the response was that SS59GV2 will only support Pentium D 805 and Pentium D 920. While 920 is hard to find in my area and not willing to step down to 805 with 133MHz FSB since I have DDR400 installed, anybody actually test the system with other Pentium D CPUs such as 915, 925, 930, etc.?