Are there limits to using fast ram in a slow system?

[Tectron]

I only ask this because my computer systems just evolve over time,I haven't built a totally new system since 2000.

Ive accumulated enough parts to step out of the socket 478/DDR realm into the 775/DDR2 arena, and would like to buy the fastest DDR2 ram I can buy and use it in the Dell e510 even though I believe it has a max mem speed of 533, that way when that mb/case gets upgraded I don't have to buy ram again.

I have always used DDR3200 in DDR2100 and slower with no problem, But I dont have a lot of experience with DDR2.

Thanks

 

[Elixer]

If you are asking, if you can use higher speed rated RAM than your system supports, then the answer is yes, it will go at the max speed your system supports. Although, not really sure why you would do such a thing, since most of the time, when people upgrade, you jump from DDR to DDR2 to DDR3 to whatever...
I would just get the best/fastest RAM your system supports, and when you build a new system, it will require new RAM anyway.

 

[drizek]

Buy the cheapest decent ram you can(probably 667mhz). There is no point in getting faster DDR2 because DDR2 is obsolete and your next system will require DDR3.

 

[brblx]

ddr2 800 is cheap and widely available, and will be fine for the vast majority of systems. the only rule is pick a speed at or above your processor's front bus speed- ddr2 800 being capable of supporting a processor on a 400mhz bus (1600mhz by intel's terms).

 

[Tectron]

Thats a good point, I guess ddr2 800 is probably my best bet. Unless I find some 1066 for really cheap.

 

[Blain]

Another issue in your "fast RAM / slow system" senario is that the Dell won't allow you to adjust voltage to the memory.

Don't get me wrong, there is high quality memory out there that's rated to run at the 1.8-1.9v JEDEC DDR2 standard.
But most people want get away with the cheapest "fast" memory, which usually means it's being slammed with higher voltage for stability.

 

[glugglug]

You are more likely to run into power limitations than speed limitations, especially with a Dell.
When I first tried to upgrade my wife's Dell from 128MB DDR266 to 1GB DDR400 that I had lying around from an old machine that had already been upgraded, it would work with 1 512MB DIMM in place but not both (no post even), because it was too much load on the memory bus.
After that machine got hit by lightning, I tried the 1GB CAS2 DDR500 DIMMs I had upgraded to and they worked fine with both sockets used as they were also lower power consuming.
Stick with economy parts, not bleeding edge sticks that require higher voltage.