i'm confused by ram speeds

[SonicIce]

say you want to by e8400. it has 333mhz fsb (1333/4). which speed ram do you need? there is no ddr2-1333?

 

[virtualrain]

You are correct.

This may help you understand the relationship between memory and FSB a bit better...
http://forums.anandtech.com/me...=2190602&enterthread=y

The fact is that DDR2-800 RAM running interleaved in dual-channel mode will saturate a 333MHz front-side bus. I would suggest some low-latency DDR2-800 RAM. It will provide you the flexibility to run at low latencies at DDR2-800 speeds or higher latencies and higher frequencies depending on how your end up overclocking. Although opting for higher frequency CAS5 RAM will also allow you to run lower clocks at tighter timings as well, so you can't really go wrong if you pick something with tight default timings for it's given speed rating.

 

[DSF]

Without going into much of an explanation, DDR2-667 is the "matching" speed. Anything that speed or faster is fine.

 

[SonicIce]

So if I bought DDR2-1200, it could handle a FSB up to 600MHz at 1:1?

And what if I bought lower than DDR2-667?

 

[virtualrain]

Most high-performance ram with low CAS timings for it's speed bin are able to clock up or down according to your overclock as needed with corresponding adjustments to timings and voltage.

For example, you could buy DDR2-800 4-4-4-8 RAM and possibly run it at 1:1 at 333MHz at tighter timings (maybe 3-3-3-8) or if you overclock your FSB to 400MHz you could run the RAM at that speed at rated timings. Finally, if you overclock your FSB to 533MHz (good luck) then you could possibly run the same ram at 533MHz with 5-5-5-12 timings.

This only applies if you buy good performance RAM.