Quantify the difference DDR2 vs DDR3

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How much better is DDR3 than DDR2 ram? And how much of a difference is there between the low end stuff and the top end?

I dont know the statistics, but I do know DDR3 is more energy efficient and is faster than DDR2. There is a noticable difference, but it not drastic. DDR3 is far better than DDR1, so if anyone is getting a computer upgrade, id defenatly get a motherboard that supports DDR3 RAM. My knowledge is kind of limited with this stuff, but I know the basics. Im not sure about the whole low end vs high end RAM thing, but it seems like RAM is RAM. I dont think its that critical, other than what type of RAM (DDR3, DDR2, DDR1, etc.)

Usually the higher end memory has ECC and cheaper memory does not. ECC memory is ideal for servers to compensate for any errors in memory. Cheaper memory does not have this and is more common in the home computer.
When upgrading memory of any type it's better to match the speeds. Not all memory is the same. The computer will only ever go as fast as the slowest component in the area.
The memory is just a holding area for many programs and the faster transfer rates mean it can be loaded into the cache. Either way, the CPU runs all the instructions from the SRAM on the die which is faster than the RAM you will ever have as it's clocked to work at the same speed as the CPU.

Newer memory has improvements that take away work from the CPU to make it work faster. In the early days the CPU did ALL the work. Now there are routines, etc to bypass the CPU an effectively increase the performance of the computer without the need of a newer CPU. Early memory types were susceptible to delays as it slowed down the CPU by being slower and the CPU waiting for the memory to complete so it can carry out the next task. DDR memory had the advantage of not waiting for the CPU, but to carry on regardless.

The known limit for DDR2 was about 800, although being DDR it probably had the FSB of 400MHz actual, but performed at 800MHz. DDR3 is set to surpass this limit. There are some settings that the DDR3 uses that seems to have slower settings compared with DDR2 beating it's DDR3 rival in some tests. Although the 1600 may be the one that will surpass the DDR2 as DDR3 has been designed not to have the same limitation as DDR2.

I got a feeling that Fuzzy just wanted some quality discussion and not really asking for buying advice.

If you are really considering what motherboard to buy, then DDR3 is certainly the way to go. There shoudn't be much of a premium over DDR2 now.

In terms of speed, according to the official spec DDR3 is a lot faster than DDR2. But that's only because JEDEC stopped ratifing new DDR2 speed grade after they moved on to DDR3. DDR3 does have some improvements on inter module connections, but they won't come into play until very high frequency. The lower voltage should also help as DRAM fabrication move to smaller process. But ultimately the RAM chips on the DIMM is what determines the speed. And DDR3 is just a interface to those chips. As the basic design of RAM chip haven't change, the speed increase comes more from Moore's law than anything else.

I think the fastest DDR2 I've seen is 1200MHz. I'm sure they could make faster versions if there's a market for it. The higher end DDR3 is usually rated at 1600 now. That usually translate into much more bandwidth but slightly wrose latency. So I think we are just crossing the point DDR3 starts to show its advantages.

In terms of quality, they all do what they are advertised. So unless you are into overclocking the RAM, price and warranty terms is what I will look for. High speed RAM itself do improve overall computing speed a little, but at a very disproportional rate. The way I see it, they are meant for CPU overclocking. (through higher bus speed)

And talking about the top end, I actually think that they are generally less reliable than the middle segment products. Before i7, all those high end parts are rediciously over-volted. I guess we should thank Intel for keeping them in check. Hopefully now that there's effectively a cap on voltage, we'll finally get quality that matches the price.

A word for ECC, usually your motherboard either requires them or can't use them. And being targeted to server, they usually has slower speed to allow for more DIMMs, lower voltage and less heat.

QFT. I upgraded a few months back, april/may'ish. The cost difference was $5-10 between the two. Unless you are going with a super tight budget, go with the DDR3 for the extra few bucks.

Mist, Keith, CloudWalker and willa, you all contributed to what I was asking. Thanks.

CloudWalker, Thats exactly it. I wanted some quality discussion.

I am thinking about a new computer(but I may wait for usb 3.0) and it occurred to me that nobody discusses ram in depth. I certainly know more now.

One can easily go find a benchmark site for ram, but sorting through all that data to get a realistic perspective on purchasing isnt so easy. The four of you have summed it up neatly.

Plus, all we seem to do in this forum is argue about whos operating system is the greatest. One thing we all agree -hardware is awesome!

Well, you have to match your memory speed to the system board, so whatever you can find in that particular niche is what you need (as previously mentioned). DDR3 is probably better, as long as your mobo can support it.

Memory changes constantly, so speces vary wildly. Overall, for a long while they just got cheaper and cheaper, tho I hear that's started moving in the other direction.

DDR stands for double data rate, if anyone don't already know. It writes (I think) on both sides of a clock tick from the crystal (if they're still using crystals...