Well "5:4" on 3200+ should use memdivider CPU/12 in 2000MHz. So its really cpu frequency that it depends on. Not the multiplyer or FSB.

So it should be something like this
10x - 200/166.67 = 2000MHz - CPU/12 divider
9.5x - 200/158.33 = 1900MHz - CPU/12 divider
9.0x - 200/163.64 = 1800MHz - CPU/11 divider
8.5x - 200/154.55 = 1700MHz - CPU/11 divider
8.0x - 200/160.00 = 1600MHz - CPU/10 divider
7.5x - 200/166.67 = 1500MHz - CPU/9 divider
7.0x - 200/155.56 = 1400MHz - CPU/9 divider
6.5x - 200/162.50 = 1300MHz - CPU/8 divider
6.0x - 200/150.00 = 1200MHz - CPU/8 divider
5.5x - 200/157.14 = 1100MHz - CPU/7 divider
5.0x - 200/166.67 = 1000MHz - CPU/6 divider
4.5x - 200/150.00 = 900MHz - CPU/6 divider
4.0x - 200/160.00 = 800MHz - CPU/5 divider


Regards