New Computer Config and Questions on DDR2

[mmcookies]

I'm thinking of buying these parts from my regional distro for my new main computer, enabling me to truly dual box along with my current one. Up till now I've been alt-tabbing between two dual logged accounts on the same computer and doing pretty well (although it does have its limitations without the fancy software/gizmos).

> Intel Core 2 Duo E4400 2.0GHz 2MB 800MHz LGA775

> Corsair TWIN2X2048-6400 2x1GB DDR2 800Mhz

> Gigabyte GA-965P-S3 i965P Chipset S775 1PCI-Ex16/3+3PCI/4DDR2 w/Sound SATA Raid GB-Lan ATA-133

> Antec Sonata III 17" Black ATX w/500W PS (8xbays)

> eVGA E-GEFORCE 8600GT 256M DDR3 PCI-E (256-P2-N751-TR)

In case you're wondering, I'm cannibalizing the hard drive and DVD from another computer.

Now I have a question about DDR2 RAM. A few years back when I bought this old computer with two sticks of DDR-400, I researched a bit and found that it was adequately matched to a 800MHz FSB because of the dual channel architecture.

Has this changed with DDR2 RAM? Everywhere I see recommendations of getting DDR2-800 while the FSB speed seemed to have stayed at 800MHz.

As far as I can tell, the popularity of DDR2-800 seems to be due to the potential for overclocking, which I might be doing somewhere down the line (I don't usually OC new chips). Let's say hypothetically that I don't plan on overclocking, would going with dual channeled DDR(2)-400 memory still be adequate?

And just what is the difference between DDR-400 and DDR2-400 anyways? The clockspeed and bandwidth both seem to be the same >_>

[Asrai]

I think this is what you're looking for: http://en.wikipedia.org/wiki/DDR2_SDRAM, or more specificly: http://en.wikipedia.org/wiki/DDR2_SDRAM#Backwards_compatibility.

Hope that answers the RAM question.

[mmcookies]

I can see where my post was misleading. Unfortunately I'm wondering more about the architecture side of things. Basic hardware stuff I can understand well enough to stick a computer together.

What I'd like to know is what're the gross performance differences between DDR-400 and DDR2-400, if any. I know that I've read the DDR2 initially had higher latency (something or other) that's later compensated by faster clock frequencies.

As for the other part, I'd like to know if overclocking is the only reason why I keep seeing people recommending DDR2-800 for E4400, or if there're other benefits I don't understand?

[Asrai]

Well, I think I got a bit carried away and veered from what you wanted to know, but in doing some research I dug up these three articles. They're quite informative, even if it wasn't exactly what you're looking for.. :)

http://www.xbitlabs.com/articles/memory/display/ddr2-ddr.html

http://www.overclockercafe.com/Articles/DDR_vs_DDR2/index.htm

http://www.digit-life.com/articles2/ddr2-rmma/ddr2-rmma-1ch.html

Sorry if it isn't what you're looking for, just felt this might help :)

[mmcookies]

ooh thanks
Actually those benchmark charts did help
Seems like DDR2-533 has only marginal gains over DDR400
And I imagine the lack of DDR2-400 can only mean it's impractical or redundant to DDR-400

I'm still wondering why people default to recommending DDR2-800 for E4400 processor tho

[Ughmahedhurtz]

DDR and DDR2 will NOT fit in the same slot. There is a "key" in the middle of the slot that's offset to one side. It's offset differently for those two types of memory. Not compatible at all.

[Asrai]

DDR and DDR2 will NOT fit in the same slot. There is a "key" in the middle of the slot that's offset to one side. It's offset differently for those two types of memory. Not compatible at all.

That was the original point I highlighted.

[mmcookies]

heh, sorry for the confusion
that was so obvious I didn't think it required clarification

realistically, my choices with RAM are limited to DDR2-667 or 800 due to price and availability
my question on the 400's is largely a theoretical one

so does anyone know why (besides OC) should I use DDR2-800 with E4400?
(note that I'm probably going to buy the 800 anyways, but I'm curious)

edit:
found out from a friend of mine that overclocking is indeed the only reason for DDR2-800. i'm going to go with this setup for now and probably upgrade the mobo somewhere down the line.