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MEMORY DDR2 DDR3 DRAM explained for the last time.


NoScream~SPARTA~
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I lost a thread, I searched and failed to find it due to the forums craps search (4 chr min) & laggy performance (forum rant over). So I'm going to do it all over again as so many seem to be falling for the NEWEST is BESTEST trap.

 

DDR2 - DDR3 DRAM WHICH ONE.

 

When Ram (Random Access Memory) became Dynamic (D-RAM) Manufacturers were quick to promote the next one as the best one but were slow to push off the old one if the last one was actually really really good & that's the problem with DDR2 v DDR3.

 

DDR3 is great as it breaks through one major flaw in DDR2, the restrictive access of memory locations in the modules by pairs. DDR3 brings the access to triplets (in three's) meaning that if you store something in memory, you can put it there in three pieces and retrieve it in three pieces.

 

example: Made simple (not real)

 

The word 'SPARTA' needs to be stored in memory, each memory location can store a letter. The CPU sends to memory via the memory hub controller the letters for storage. The memory controller sends a request to write the letters 'S P A R T A' into memory.

 

In our example lets make things even simple & say our memory has these properties:

Request to write memory, Read Time, Delay between operations, Min Module delay between nothing happening.

 

Our memory module has a fictitious setting of 10-10-10-30

Our module needs 10 cycles (of the memory clock, ticks) to get ready for a write, it needs 10 cycles to read out a value, it needs 10 cycles of delay between any operation. The total loop time is 30 cycles, to do something.

 

Back to 'S P A R T A'

 

S

Request from Memory controller to memory module to store (write) = 10 cycles

Write in a value = 10 cycles

Delay = 10 cycles

 

P

Request from Memory controller to memory module to store (write) = 10 cycles

Write in a value = 10 cycles

Delay = 10 cycles

 

A

Request from Memory controller to memory module to store (write) = 10 cycles

Write in a value = 10 cycles

Delay = 10 cycles

 

R

Request from Memory controller to memory module to store (write) = 10 cycles

Write in a value = 10 cycles

Delay = 10 cycles

 

T

Request from Memory controller to memory module to store (write) = 10 cycles

Write in a value = 10 cycles

Delay = 10 cycles

 

A

Request from Memory controller to memory module to store (write) = 10 cycles

Write in a value = 10 cycles

Delay = 10 cycles

 

---------ALL DONE -----------

 

NOW DDR2

 

DDR2 is special as it does the same as DDR1 (DRAM but with two modules together, so if it was to store something it would do it two by two.

 

 

Back to 'S P A R T A' Again but now for DDR2, each DDR2 module saves one element of 'SPARTA', see how much quicker things are??

 

S P

Request from Memory controller to memory module to store (write) = 10 cycles

Write in a value = 10 cycles

Delay = 10 cycles

 

 

A R

Request from Memory controller to memory module to store (write) = 10 cycles

Write in a value = 10 cycles

Delay = 10 cycles

 

 

T A

Request from Memory controller to memory module to store (write) = 10 cycles

Write in a value = 10 cycles

Delay = 10 cycles

 

---------ALL DONE -----------

 

NOW DDR3 (Triple Channel / 3 writes)

 

DDR3 is special as it does the same as DDR2 (DRAM but with three modules together, so if it was to store something it would do it three by three.

 

 

Back to 'S P A R T A' Again but now for DDR3, each DDR3 module saves one element of 'SPARTA', see how much quicker things are??

 

S P A

Request from Memory controller to memory module to store (write) = 10 cycles

Write in a value = 10 cycles

Delay = 10 cycles

 

 

R T A

Request from Memory controller to memory module to store (write) = 10 cycles

Write in a value = 10 cycles

Delay = 10 cycles

 

 

 

 

Wow DDR3 is the NUTZ!!, DDR3 'U' RocX my World !!

 

But stop, this is only the first element of the MEMORY PUZZLE......

The other element is the CLOCK that makes the CYCLES that the whole memory system lives on

 

 

THE CLOCK CLK

 

 

So DDR2 typically runs @ 400Mhz (that is 400 million times a second, Mhz just means Million times a second.)

DDR3 typically runs at around 666Mhz (wow faster !! (you rokX DDR !!)

 

800 & 1333Mhz you say??? I say not, remember manufacturers like big numbers, they quote the transfer rates normally and not the CLOCK rate because the memory is 'DUAL DATA RATE (DDR), to confuse you more, the BIOS on boot quotes the Data rate & actual Clk, like Corsair DDR 800 @ 403Mhz, now you know why....

 

 

 

But now back to the real world for some real world numbers.............

 

 

THE FIGHT

 

 

Some cock sucking value DDR3 off the peg.....

http://www.cclonline.com/product/43399/CMX2GX3M1A1333C9/Desktop-Memory/Corsair-XMS3-memory-module-2GB-1x2GB-1333MHz-9-9-9-24-1-5V-for-AMD/RAM1194/

 

1333MHz 9-9-9-24

 

 

Runs @ 1333Mhz(data rate / 666 Clock) has access times that total 24 CLOCK CYCLES to DO something like store...... and RUNS in BANKS of 2 or 3 depending on your system.

 

 

Some cock sucking value DDR2 off the peg.....

http://www.cclonline.com/product/19112/TWIN2X2048-6400/Desktop-Memory/2GB-Corsair-XMS2-800MHz-DDR2-Dual-Channel-Memory-Kit/RAM7508/

 

800Hz 5-5-5-12

 

Runs @ 800Mhz(data rate / 400 clock) has access times that total 12 CLOCK CYCLES to do something like storing ... and runs in banks of two only.

 

 

WHICH ONE IS FASTER ?

We stick to Data rate for now but the comparison is valid as long as your always quoting the same / like for like.......

 

 

1333Mhz DDR3 with 24 cycle time in banks of two and/or banks of three Verses 800Mhz DDR2 with 12 cycle time in Banks of Two...

 

 

How to work it out....

 

 

How many cycles can a memory module do in one SECOND is the real question. (Higher is better)

 

Answer = the speed in cycles (Mhz) divided by the cycle time.

 

 

DDR3 (Triple) 1333/24 = 55 x 3 modules (55 x 3) for triple module system - 165

DDR3 (Dual) 1333/24 = 55 x 2 modules (55 x 2) for dual module system - 110

 

DDR2 (Dual) 800/12 = 66 x 2 modules (66 x 2) for dual module system - 132

 

 

 

I've simplified the whole business of MEMORY but I hope you can see the pit falls and market screwing with figures to bias some things against others. Here we see one thing the slow DDR3 (24 cycle) in triple channel is the fastest, the second fastest is the DDR2 in dual channel by about 15%, the slowest is the DDR3 in dual channel mode, Shock horror.....

 

It's a simple fact, DDR3 is a buzz word, DDR2 is cheaper to make, some manufacturers are buzzing instead of giving you the best system.... compromise means cheaper prices but not the best solution.....

 

 

All spelling mistakes & over simplification of the complex world of computer memory is intentional.......

 

:beatdeadhorse:

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Vii !!! I Love you Man ! :)

 

However.. are you a teacher in real life? .. never knew what s your business, but you have an amazing way to explain electronic :)

 

I think I will steal some of your concepts if I will find myself to help some friends... and bytheway, if you will write a book, I am gonna buy it ! :)

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So, let me ask you this...

 

Actually I have a set of 3 x OCZ 2048 pc3 1600, timing 9-9-9-24

 

Honestly I am happy with that, couldn t say any inconvenience ongoing.

 

Due to very low price per RAM, after your illuminating discussion, I saw this one:

 

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231352

 

Timing 6-8-6-20 quite affordable price.

 

It makes any sense? i mean of course it looks better, possibly is faster and bla bla.. but, in real life, it is valuable of my 100 bucks ? :)

 

Thx :)

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DDR4 will be another big step & hopefully give a better gain differential for performance.

 

DDR4 moves from channels (DDR - 1 channel, DDR2 - 2 channel, DDR3 - 2 or 3 channel) to point to point. Memory modules per channel, ddr2 & ddr3 could be 2 or 3 modules, all modules per channel would have to wait while the others were being talk to by the controller. Point to point means one channel for one module.

 

Six DDR4 dimms would mean six channels..... yum yum.... 6 x 4GB (24Gb) DDR4 Dimms on 6 channel instead of 3 like DDR3 triple channel... 4 DDR4 dimms would be talking on 4 channels.

 

Each 'CHANNEL' has a max speed, so using an analogy, a 3 lane highway with a max speed limit of 200MPH (300KPH) would have the same difference as moving to a 6 lane highway @ 200MPH but the makers are also upping the speed limit too.......

 

 

:thumbsup_anim:

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And yet, I'll likely never notice the difference for any of this. XD

 

I have 8GB of 1333 DDR3 (4GB x 2) and I've yet to ever even reach much past half capacity. I think the most important question is: will the average gamer ever even notice a difference? Especially with the added price tag of a third stick? Is the price worth the gains in performance (if any)? I know "enthusiasts" scoff at this, but most of us want a practical solution at a cheap price.

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Everyone wants a good price but even at the expense of future ability....

 

 

Memory is a key component of a PC system, no one notices till it's too late, like a CPU with 4,6,8 cores totally useless? who needs them till they do need them, then it's too late to reposition & be there when it is required.

 

My system is two years old and is well positioned (in my opinion) for games like Arma 3, Battlefield 3, photoshop CS5, Corel Video Studio editing, all the requirements are not called for till the programs calling for them are released but to use any of them as the manufacturer demonstrates requires big horse power from the system. True many can use them all with lesser systems but not with the fluidity the developer demonstrates in many presentations.

 

My two year old PC requires no upgrade today or next year, I bought memory when it was cheap & then it sky rocketed, it once again is cheap, but the problem is which memory is key to other key components, some developers are led by business, sales & turn over to the next progression and not led by what is best bang for the $$$.

 

With memory, DDR3 in triple channel is key but not by much but still the extra ability gives the user a better flow of data, just like a key CPU or key storage unit.

 

 

Overall, setting a budget and working in as many key components it the best way to be prepared for the software that the user will use one day that will push the limits.

 

Today DDR3 being sold in dual channel systems is on balance not as good as a system using DDR2 in dual channel when the CAS (CL) is so bad on DDR3 in comparison to DDR2 with it's uber low Latency.

 

 

 

KEY PC COMPONENTS are ones that deal with data flow as that's the function of a PC at it's core (data processing)

 

CPU

GPU

SYSTEM MEMORY

VIDEO MEMORY

STORAGE UNIT

INTERCONNECTION INFRASTRUCTURE (Motherboard)

 

DDR2-400 DDR2-533 DDR2-667 DDR2-800 DDR2-1066

DDR3-800 DDR3-1066 DDR3-1333 DDR3-1600 DDR3-1866 DDR3-2133

 

 

It's not only the speed but also the amount.

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Well, the way I see it we wont see a major leap in gaming/graphics technology that pushes this hardware until the next generation of consoles (more precisely, the next Playstation). It's sad, but it's just the way things are right now. It's where the money is. Sure, there are fringe titles here and there that continue to push the limits (Metro 2033, ArmA 3, etc) but for the most part everything is made with the idea of keeping console compatibility in mind. Even BF3, a stunning achievement, isn't really that big of a leap from BC2. They just took lessons learned from the two BC's, primarily console games, and scaled it for PC and optimized it much better.

 

Being future-proofed is always a good thing, but I think the average gamer has the ability to lower their graphical standards to meet a budget. I can always add a third stick if I really felt I needed it. But I also played games on low/medium settings and very low resolutions (like, 1024x768 and below) with FPS averaging around 30 for many, many years and was totally content. I personally don't notice any significant difference after 50-60 fps.

 

Not trying to sidetrack the conversation or anything. This post is very informative and well-written. I'm merely playing devil's advocate (as I love to do XD) and ask whether any of this is completely necessary.

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Excellent presentation of the facts Vii, I would expect nothing less to be completely honest with you. I have been saying this for years and I constantly had to defend the technology (not because I am a fanboi but because it is sound mathematics).

I always say "If you can afford to embrace a new technology, do so, it guarantees technological advancement"

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  • 1 month later...

I'm gonna ask a dumb question, but I have an Intel....(lemme look, it's been so long since i upgraded!)...Q9550 processor at 2.83ghz. It's currently got 4gb of DDR2 memory in it. Will I be able to use DDR3 in this same setup? Will I have to get rid of the DDR2 and use only the DDR3? Can I even use DDR3 at all? I'm looking right now for some extra memory just to boost things up a bit, without having to get an entire new processor+mobo, so any help would be greatly appreciated!

 

EDIT: This is what I currently have: OCZ Gold 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Dual Channel Kit Desktop Memory Model OCZ3G16004GK

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