A user at Xtremesystems forum that goes under the screen name Ivanqu has managed to get the FSB on MSI's P45 motherboard up to 640MHz on air. According to the rest of the posts at that thread this is possible on both MSI P45 Platinum and MSI P45 Neo2-FR as both have the same PCB.

The best score that Ivanqu managed to score is 4234.65MHz on Core 2 Duo E8400, or 705.78 x 8 FSB configuration. The 705 FSB result is done using an LN2 cooling, but according to another post this configuration can also do a bus speed of 640 with air cooling. We must note that this was done with only 512MB of memory and with only one core, as the other was apparently disabled, but anyway, this is still a great result.

You can check out the forum thread here, and you can find the CPU-Z validation here.