it'll run its rated speed but like the CAS rating, it won't run aggressive ones well or overclock well (you might get lucky and get one that does however)

the 2 rams linked in the thread both are rated at 400mhz and
HyperX Cas Latency: 3-4-4-8-1T (my HyperX stick won't do 1T even though its rated for it as well)
Corsair Cas Latency: 3-4-4-8

I have higher quality Mushkin PC3000 (DDR366 I believe? got it a while ago) ones that are rated similar in CAS but I'm able to push the speed to 400mhz easily and my CAS rating is alot more aggressive (2-2-2-?-1T).