Question DDR2 800 VS DDR2 533 as well as HT question

[Etherian]

Hey all I have a question. Most of the benchies I've found don't find a huge improvement in performance( at least for now) using slower DDR2 Ram over the higher speed in actual performance. So given that I can get DDR2 533 right now for almost a third less than the DDR2 800 stuff I'm definately giving it a look.

Thing is when I browse a store say like new egg, the mobos have a field DDR2 Standard: *Ram speed*

Can I use slower stuff in the motherboard or do I have to use 800?

I'm only looking at going with an X2 4200 cause of the cheaper mobo that can support 4 ide devices, and dual channel on the memory,full form ATX and was curious if the 533 would bottleneck it a whole lot. Used to just look at the FSB but now they're all using HT(at least on the amd side) and I have no idea how you decide how fast of RAM you need from that number.

 

[sithscout80]

Intel's new Core 2 Duo processors aren't very affected by the speed of the RAM. AMD's newest chips for socket AM2 are very RAM dependent. The faster the RAM (and lower latency) affects the chips quite a bit.

For motherboard compatibility. As long as the motherboard supports a higher speed, it will work.

FSB and HT. For AMD's chips, the IMC (Integrated Memory Controller) handles any speeds of RAM. Intel's FSB does the same thing, though with the FSB, you may have to run the RAM and FSB at a ratio.

 

[toddbailey]

one thing you forgot to mention is memory voltage.

I just purchased a Asus m2n4 board and it doesn't support the higher voltages that some of the ddr2-800 memory needs.

I had to rma the g.skill to find something lesser than I wanted so the board would work.

 

[sithscout80]

Thanks for the voltage addition. Another interesting thing I've found on Intel motherboards is something called Flex Memory Technology. It essentially allows you to run Dual-Channel Asymmetric (with better performance than single channel, but not as good as true dual channel).

Here for more info on Flex Memory Technology.

 

[RickGG]

FSB and HT. For AMD's chips, the IMC (Integrated Memory Controller) handles any speeds of RAM.

What is the base or core speed of the IMC? For example, in looking at DDR2 800, do I assume that the IMC is using the reference clock speed of 200 Mhz, DDR'd to 400Mhz X 2 for a total of 800?

Thanks,

Rick

 

[sithscout80]

200MHz is the reference clock that everything is based on. For DDR2 800MHz, the 200MHz clock is doubled to 400MHz so it is the same speed as your 800MHz (effective RAM). The CPU speed is the same way, take the reference clock and multiply by the multiplier to get the processor frequency.

 

[Dahak]

Actually the 800 ram is significantly better for over clocking an amd chip than the 533.The slower ram,although not noticable will not run quite as fast as the other ram,thereby not letting you get the full potential out of your system.Goodluck.

Dahak

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