How much better is 667MHz DDR SDRAM Vs. 533MHz DDR SDRAM?

I am going to buy a HP Compaq nc8430 and there are 2 configurations and I am not sure which one I should go for. One is $1949 and has 1GB 667MHz DDR SDRAM (1 DIMM) the other that is $1749 has 1GB 533MHz DDR SDRAM (2 DIMM) and comes with a DVD+/-RW vs a DVD/CD-RW Combo other than that they are exactley the same. So for $1749 the Ram isnt as good but you get a better optical drive.

So my question is should I spend an extra $200 for the better Ram...I dont really care about the better optical drive? If I get the $1749 one I will buy a 1GB DIMM so I would have a total of 1.5GB. Can I buy a 667MHz DIMM if the 512mb DIMM is a 533Mhz or do they have to be the same speed?

Also how much better is the 667MHz compared with the 533MHz when it comes to RAM?

 

Id go with the 533mhz ram, 667 has higher latency which in some cases results in poorer performance also your getting dual channel ram in the 533 configuration doubling your bandwidth.

 

I asked this question a while back, so I'll tell you what I've learned from the people here Yea, you can do it, but the 667MHz stick will be downclocked to 533MHz.

 

I would not shell 200$ extra for the newer ram.
BUT, the 200$ extra one is 1 DIMM, thus u cood buy a 1 GB stick to make it 2GB RAM total. Final price = 1950+1 stick of ram
For the other one, you would need *2* 1GB sticks to make it 2GB ram. Thus final confiuration = 1750+2 sticks of 1gb ram
Something to keep in mind

 

Thats if you want 2 gigs or ram andif you take a look at a recent poll "how much ram do you have" 2 gigs is overkill in 99% of systems.