You are using DDR (DOUBLE data rate) so need to take the true freq as shown in CPU-Z's memory tab times 2 to get effective freq of near 667 - can find a couple more tidbits about CPU-Z in an info thread I wrote here:
Blackbird you beat me to it 😉 so I'll double that with another What!!!!! needs to actually look at it - CPU-Z even displays the FSB to DRAM ratio right under freq (at least I'm pretty sure it the spot under, will correct myself if I'm wrong
The cause of low performance should be the Pentium 4. It is time to upgrade if you have the coin. If not, I suggest you use Linux instead of Windows, your PC will perform better. Try Lubuntu.