DDR3 speed vs DDR2

Crashgate3 · 11 May 2008 at 22:57

I'll be building a new PC in a few months. I'd like to say that money is no object, and it *almost* is, but within reason. I know that if you're trying to get a sensible amount of performance/cost then DDR2 is the way to go at the moment. Thing is, I can afford to get DDR3 if it really is faster, but, well.. is it noticably faster (as opposed to just on paper)?

If there's not really any difference I'll save myself the money.

steve258 · 11 May 2008 at 23:03

removed

Reality|Bites · 12 May 2008 at 10:54

Ok

Say you had your FSB and Memory 1:1

Say you had your DDR2 @ 400Mhz timings of 4-4-4-10
Say you had your DDR3 @ 400Mhz timings of 8-8-8-20

Now DDR3 can transfer twice as much per cycle compared to DDR2 but each cycle takes twice as long so they effectively have the same bandwidth.

It's only when you get past DDR2' frequency limit (600Mhz or so) that DDR3 comes into it's own.

When a CPU is released with a FSB of 600Mhz or more, That would be the right time to buy into DDR3.

thegoonden · 12 May 2008 at 11:14

Of course if you are building a new box and expecting it to last you a while, there's not much point using old tech.
The DDR3 I have (corsair 1600) has 7 7 7 20 timings so I suppose that makes it a tweensy bit quicker, though certainly not anything to jump for joy about. Then again, I chose it because this box is meant to last 3-4 years, and I want it to be on one motherboard.

helmutcheese · 12 May 2008 at 18:16

steve258 said:
That's the thing DDR3 isn't really any faster due to rediculously high timings, same when DDR2 first came out. Wait until DDR3 manufactures mature with higher speed and lower timing kits availble before even thinking of making the change.

The Timings are NOT compairable.

I aint going to repeat so will quote my last post on topic.

Quoted :

" You cant compair the Timings on DDR to DDR2 to DDR3.

Fastest DDR was Corsairs 400mhz 2:2:2:5

I think thats about the same as DDR2 800mhz @ 4:4:4:4:10 (Mushkin) and DDR3 1600mhz @ 8:8:8:8:20, you can get likes of DDR3 1600mhz @ 7:7:7:7:18 (G-Skill). "

Reality|Bites · 12 May 2008 at 18:42

but your missing one part of the equazion.

DDR2 transfers double the data compared to DDR1
DDR3 transfers double the data compared to DDR2

You have to keep the frequency the same to compare them not double them as your doing.

DDR1 PC4400 250Mhz 2.5-3-3-6 was close enough to DDR2 PC4200 266Mhz 5-5-5-15(when first released)

So at that time there was no advantage in going DDR2, Same thing is happening now with DDR3.

lets make it simple then.

DDR1 @ 200Mhz DDR400 2-2-2-5 Transfers double per cycle compared to SDram
DDR2 @ 200Mhz 4-4-4-10 Transfers double per cycle compared to DDR1 each cycle taking twice as long compared to DDR1
DDR3 @ 200Mhz 8-8-8-20 Transfers double per cycle compared to DDR2 each cycle taking twice as long compared to DDR2

So they would all have the same effective bandwidth in this case.

helmutcheese · 12 May 2008 at 18:47

Not really, the Freq Doubles so does the Timings.

The above info is accurate if you stick to DDR 400 v DDR2 800 v DDR3 1600 for compairisons.

Saying the Timings are bad on DDR3 1600 because they are 8:8:8:20, is the same as saying there bad on DDR2 800 at 4:4:4:10 and DDR 400 @ 2:2:2:5.

Reality|Bites · 12 May 2008 at 18:51

I'm not talking about what is actually on sale in shops.
I'm talking about how the memory actually works and how you can compare them.

Just because you say we can't compare them doesn't make it so

If the frequencies are the same you can compare them.

helmutcheese · 12 May 2008 at 18:53

Ive already debated how DDR3 works in other threads along with others inputing so dont need to do so again.

Im talking the fact 8:8:8:20 are not bad Timings for DDR3 @ 1600mhz Memory, because DDR2 commonly is 4:4:4:12 at 800mhz

Some peeps see the higher numbers and dont have a clue.

Reality|Bites · 12 May 2008 at 18:56

Yeah once we get a CPU with an 800Mhz FSB that 800Mhz DDR1600 memory will come in handy

thegoonden · 12 May 2008 at 18:57

So, errrm hang on....my uberbox has the same memory bandwidth as the DDR1 box I just decommissioned??
(ish)
(1600 and 400 respectively)
DDR1 is like free with cornflakes these days, sign me up for the Quadcore board with 8 DDR1 slots please

helmutcheese · 12 May 2008 at 19:01

Reality|Bites said:
Yeah once we get a CPU with an 800Mhz FSB that 800Mhz DDR1600 memory will come in handy

Not really needed, Asus Mobos (NF anyhow) now class 1:1 as the FSB and CPU both at same DDR speed ie 1333mhz Quad Pumped CPU FSB and 1333mhz DDR Memory speed.

If I set to CPU to 1333mhz and Memory to 667mhz Asus Bios does not class as 1:1, its classed as LINKED and IN SYNC.

In your case we do not even need DDR3 then.

Nice info I read only today.

http://benchmarkreviews.com/index.php?option=com_content&task=view&id=174&Itemid=1

Reality|Bites · 12 May 2008 at 19:02

Your DDR1 ran at 200Mhz DDR400
Your DDR3 runs at 800Mhz DDR1600

Your DDR3 has 4x the frequency, 4x the latency, transfers 4x as much per cycle.

So that you be two plus and one minus.

if you could get your DDR1 up to 800Mhz from 200mhz you could compare them.

As it stands your DDR3 800Mhz DDR1600 has 4x the bandwidth it think(confusing myself now)

Reality|Bites · 12 May 2008 at 19:05

Just because it's marketed as being 1:1 doesn't make it so does it.
Bigger numbers sell more products that's all.

remember the link I gave you to the eVGA forums?

We don't need DDR3 yet though.

helmutcheese · 12 May 2008 at 19:05

Yes, and thats why the Timings are Compairable as not being bad in the examples I made.

You aint going to see CAS 2 DDR2 or CAS 4 DDR3 AFAIK its not possible.

Reality|Bites · 12 May 2008 at 19:18

never said you could

p4radox · 12 May 2008 at 19:25

helmutcheese said:
Fastest DDR was Corsairs 400mhz 2:2:2:5

What about the Geil One TCCD CAS1.5 stuff?

Is DDR3 the only RAM type on which triple-channel will be available? If so, that might make it finally worth the jump.

helmutcheese · 12 May 2008 at 19:31

p4radox said:
What about the Geil One TCCD CAS1.5 stuff?

Is DDR3 the only RAM type on which triple-channel will be available? If so, that might make it finally worth the jump.

Thats already been mentioned in other thread.

V|per said:
Geil 1???

But i agree, i would not call those timings bad, there is even a 2000mhz kit out now, cas 9 i believe.

helmutcheese said:
Actually CAS 1.5 was as low as it went AFAIK and i aint even sure that was offically.

steve258 · 12 May 2008 at 22:51

helmutcheese said:
Saying the Timings are bad on DDR3 1600 because they are 8:8:8:20, is the same as saying there bad on DDR2 800 at 4:4:4:10 and DDR 400 @ 2:2:2:5.

OK fair enough.

DDR3 still isn't worth the money though which ever way you look at it.

helmutcheese · 13 May 2008 at 00:23

Who cares ?, DDR3 is where the futures at and 2GB of Branded DDR2 cost £146 last April (2007).

Esp true as next Chipsets out will no doubt drop support for DDR esp when the Memory Controler will be in the CPU's same as AMD's.

Oh, and that does not change the fact your comment about Timings were 100% wrong, so a little dig at price is pointless, if you had commented about DDR3 being waste of money I would not have even replied.