I would expect the Memory controller to be the FSB speed because (at least as far as I thought) the memory controller effectively is The front-side bus.
I was thinking same thing, but this system started off with running on 1.5GB of mixed 533Mhz DDR2 sticks years ago when RAM from a prior Pentium 4 that ran on DDR2 533Mhz was migrated forward in this low cost gaming build, then I upgraded it to 2GB of 667Mhz DDR2 when I found some 1GB sticks from a dead system that were good, and then 5 year ago I bought a ASUS P5Q Deluxe motherboard, Core 2 Duo E6600 CPU, and 4GB Corsair XMS2 DDR2 800Mhz RAM from my brother for $100 and the 4GB RAM I installed to this system and then upgraded from 32bit to 64 bit Windows 7, and the CPU went into my wifes system as an upgrade to the socket 775 Celeron D 2.53Ghz and gave away the motherboard to a friend, and I assumed that the memory controller ran at multiple clocks based on the wide range of RAM it supports. Such as I have run this Athlon II x4 620 on the older 533Ghz DDR2 which is slower than 667... *However.. maybe the 533 could have been run at 667 overclocked without manually overclocking the RAM, but I am thinking it actually ran at 533Mhz. And the 800Mhz RAM could be running underclocked at 667Mhz.
Not that big of a deal as for the system runs healthy. Its just that it caught my eye as odd that they have it listed at 667 yet this CPU I have run on multiple different RAM speeds and type and it runs on them such as the DDR2 ( 533, 667, 800Mhz ) in the Biostar MCP6PB M2+ motherboard, and DDR3 ( 1333Mhz ) in the Biostar A960D+ motherboard.
Both boards here:
MCP6PB M2+ :
http://www.biostar.com.tw/app/en/mb/introduction.php?S_ID=387#memorysupportA960D+ :
http://www.biostar.com.tw/app/en/mb/introduction.php?S_ID=627#memorysupport