DDR1, DDR2, DDR3: Navigating The RAM Maze

Which DDR Is Which? Here Is A Full Guide To RAM.

Many computer enthusiasts know exactly what they want when they go to configure their new system. They've researched and picked out a perfectly matching CPU, motherboard and videocard combination that will meet all their needs. However, when it comes to RAM many users become totally befuddled. They generally know how much RAM they need (1GB is the effective operating minimum these days, 2GB if running Vista or using hungry apps like Photoshop), but they don't have a clue as to what DDR1, DDR2 or DDR3 means.

It turns out that selecting the proper DDR variant is a very important factor that determines how your overall system will perform, thus every enthusiast/prosumer/gamer should be well-advised to learn the basics.

Choosing the proper DDR-variant for your PC is critical!
Choosing the proper DDR-variant for your PC is critical!

Double Data Rate DIMM is known as DDR-DIMM, DDR DIMM, or most popularly just plain DDR. Double Data Rate interfaces provide two data transfers per differential clock. The data becomes registered when the CK goes high [the + side], and /CK goes low [the - side]. DDR1 utilizes the JEDEC standard for Double Data Rate [DDR I] SDRAM. Like all DDR RAM it is available as registered or unbuffered. Registered DIMMs are generally known as FB-DIMMs and have their address and control lines buffered in order to reduce signal loading. FB-DIMMs are considerably more expensive than unbuffered DIMMs and are generally reserved for server use. There are very few enthusiast/prosumer/gamers utilizing FB-DIMMs in their rigs. Unbuffered DIMMs don't feature address lines and control line buffering, so they cost quite a bit less. However, they may be system-loading limited and are thus generally restricted in the number that can be fitted onto one system. You'll find that most unbuffered DIMMs these days can only be installed on one motherboard to a maximum of 4 x 1GB. Buffered or registered DIMMs don't have these limitations and server boards can accommodate 8 x 1GB, 16 x 1GB or more. An interesting and largely unknown aspect of unbuffered DDR DIMMs is that they are able to operate one clock cycle faster then FB-DIMMs.

DDR2 memory is the second generation in DDR memory. DDR2 begins with a speed level of 400MHz as the lowest available while the 400MHz speed is actually the highest speed for DDR1. Therefore, DDR2 picks up where DDR1 leaves off. It's a bit strange but due to different latencies a 400MHz DDR1 will outperform a 400MHz DDR2, but the advantage returns to DDR2 as soon as the speed reaches the next step 532MHz, which DDR1 cannot reach.

It follows that DDR3 is the third generation in DDR memory. DDR3 begins with a speed level of 800Mbps (400MHz) as the lowest available. As of May, 2010 (a full three years after the rest of this Hub was written) the highest popularly available DDR3 speed is represented by the Patriot Viper II Series Sector 5 Edition PC3-20000 2500MHz modules!

Adding to customer confusion is that RAM is often referred to as a DDR-number or a PC-number. (The Revenge of the Geekizoids continues.) Here is a Chart for the various currently common DDRs as of May 2010:

Current DDR2

  • DDR2-400. Memory Clock: 100 MHz. Bus Clock: 200 MHz. Data Transfers/Sec.: 400,000,000. Module Name: PC2-3200.
  • DDR2-533. Memory Clock: 133 MHz. Bus Clock: 266 MHz. Data Transfers/Sec.: 533,000,000. Module Name: PC2-4200.
  • DDR2-667. Memory Clock: 166 MHz. Bus Clock: 333 MHz. Data Transfers/Sec.: 667,000,000. Module Name: PC2-5300.
  • DDR2-800. Memory Clock: 200 MHz. Bus Clock: 400 MHz. Data Transfers/Sec.: 800,000,000. Module Name: PC2-6400.
  • DDR2-1066. Memory Clock: 266 MHz. Bus Clock: 533 MHz. Data Transfers/Sec.: 1,066,000,000. Module Name: PC2-8500.

Current DDR3

  • DDR3-800. Memory Clock: 100 MHz. Bus Clock: 400 MHz. Data Transfers/Sec.: 800,000,000. Module Name: PC3-6400.
  • DDR3-1066. Memory Clock: 133 MHz. Bus Clock: 533 MHz. Data Transfers/Sec.: 1,066,000,000. Module Name: PC3-8500.
  • DDR3-1333. Memory Clock: 166 MHz. Bus Clock: 667 MHz. Data Transfers/Sec.: 1,333,000,000. Module Name: PC3-10600.
  • DDR3-1600. Memory Clock: 200 MHz. Bus Clock: 800 MHz. Data Transfers/Sec.: 1,600,000,000. Module Name: PC3-12800.
  • DDR3-1800. Memory Clock: 225 MHz. Bus Clock: 900 MHz. Data Transfers/Sec.: 1,800,000,000. Module Name: PC3-14400.
  • DDR3-1866. Memory Clock: 233 MHz. Bus Clock: 933 MHz. Data Transfers/Sec.: 1,866,000,000. Module Name: PC3-14900.
  • DDR3-2000. Memory Clock: 250 MHz. Bus Clock: 1000 MHz. Data Transfers/Sec.: 2,000,000,000. Module Name: PC3-16000.

Now which CPU/chipset matches which RAM? It would take an encyclopaedia to list all the CPUs and all the chipsets and their "best-fit" DDRs. Before finalizing your system configuration you should research your CPU manufacturer's RAM recommendations and fit that exact type of DDR to it. You would be just as foolish in using a PC3-12800 DDR3-1600 with an AMD Sempron 2800+ as you would be to burden down your Intel QX6800 with a PC1600 DDR-200. Every CPU/chipset combo has its proper DDR fit, and you should find out exactly what they are and stick to them. Fitting a slower than recommended DDR to your system will bottleneck critical RAM functions and could slow your otherwise very speedy system to a tortoise crawl.

There are many other factors involved in choosing the right RAM for your rig. Latencies are critical, but the details are too extensive to include here and will form the basis of a future blog. There are also a mind-boggling array of RAM brand names and pricepoints. Generally, you get what you pay for and as long as you are comparing various brands at the same retailer, the price will be a fairly good indicator of quality. Some of the leading manufacturers include:

Centon

Corsair

Crucial

Kingston

OCZ

Patriot

A couple of more points to remember. First, RAM heat spreaders may or may not be worth the extra cost. I can see that they would be useful only in the tiniest minority of high-load, prolonged-heavy-use situations. Don't ever touch your RAM (or other PC internal components) without being thoroughly grounded with a good static strap. Static can zap your circuitry before you know it.

If you follow these guidelines and thoroughly research the proper DDR for your system, you'll be rewarded with years of speedy and trouble-free computing. A bit of prior study is a small price to pay!

 

Check out hundreds of Hal's PC Technology articles in these categories:

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Comments 84 comments

The Lokaine Narra profile image

The Lokaine Narra 9 years ago

Thank you for this blog. I was hoping someone would tackle the RAM issue, and you did a superb job!!


kenneth delos reyes 9 years ago

Thanks this is what I really need. I learn the differences between ddr1, ddr2 and ddr3. Thanks again.


MGM profile image

MGM 9 years ago from Goodyear

what about Dual Channel DDR you forgot to mention that, I bought this new motherboard and just reagular 182 pin DDR and the bord did not respond at all, I ordered 2 GB duel the other day hope it gets here soon so I can test it out on my bord to see if I didn't ruin anything.


OneShot profile image

OneShot 8 years ago

Great Post! I am about to upgrade and understanding the RAM issue a little better is going to help tremendously. Thanks!


deepak  8 years ago

this is a fantestic idia to used DDR3 in PC


MrMarmalade profile image

MrMarmalade 8 years ago from Sydney

You are of a great help. I am purchasing soon and now I lmow a little more than I did yesreday

Thank you


gooadam profile image

gooadam 8 years ago from san mateo

Thanks, now i can upgrade my PC.


battery 8 years ago

good tips ,very helpful,thanks


Danny 8 years ago

I have found this site very helpful. Although, it could show whether each RAM type is simm or dimm.


r0cks0ul 8 years ago

hi, im still confuse with this im planning to buy a memory my computer is an old system it only supports DDR200/266 im currently using pc2700 256mb and another pc3200 256mb memory as you can see it is working with pc3200 memory wherein it should only be pc1600/PC2100 only and what im thinking is that can i use 2x 1gb pc3200? will it work?


r0cks0ul 8 years ago

Hey good news it worked!!!!!

i bought 1 pc. of 1GB PC3200 TwinMOS memory put it on my computer and VOILA!!!!! it worked!!!!!!


AndyBaker profile image

AndyBaker 8 years ago from UK

This has always been something that troubles me. I could do with a few more gigs of ram...


solarshingles profile image

solarshingles 8 years ago from london

I recently upgraded my system RAM and it is truly amazing, how faster and smooth everything works, now.

Check this link, they have automatic software, which tests your computer about everything you need to know about memory upgrade:

http://www.crucial.com/uk/

They are all over the world, not just in UK. They really have wonderful service, which is not usual in UK technical market, at all.


PKD 8 years ago

very good. lot of new information for me. thank you. i need your help for my machine.

My PC (Model Pavillion t730i)has Intel P-4 processor 515 2.93 GHz, 1 MB L2 Cache, 533 MHz FSB 90 nm, 256 MB, 400 MHz DDR SDRAM. I want to add 512 MB/1 GB/2 GB RAM. Pls send me detailed specifications and brand which is compatible with it so that I can buy it from the market. If DDR2 can be used?


compu-smart profile image

compu-smart 8 years ago from London UK

This hub is excellent for anyone who needs to know more about RAM....including me!!..I do know, more Ram is always merrier!


Cristian 8 years ago

de cuando esta data, es confiable?


joaojeronimo profile image

joaojeronimo 8 years ago from Maputo, Mozambique

Great hub :)

Is it better to have 2 RAM chips of 1GB each or to have 1 chip of 2 GB ?


Hal Licino profile image

Hal Licino 8 years ago from Toronto Author

There really isn't a set standard. Most motherboards can handle only one chip in the RAM slots while a very few of the older ones require an equal amount of RAM in increments of two. Check your motherboard user manual for which applies to you.


saket 8 years ago

How wud i know wat's my pc's ram config?Is ddr sd ram a ddr1 ram?Can i add ddr2 ram in my pc?


Hal Licino profile image

Hal Licino 8 years ago from Toronto Author

I THINK you're asking about how to find out what type of RAM your PC needs. Just run the free and superlative Crucial System Scanner tool at www.crucial.com. You'll get a full report as to the type of memory you need for your computer.


Ronald Daniar 8 years ago

Great hub.

I just know that there is already DDR 3.

Thanks for sharing!


amoxicillin 500 7 years ago

Great Hub. Very technical but very useful! It's always to know more.


newcapo 7 years ago

Very helpful hub, thanks man


Krishna 7 years ago

HI,

Thanks a lot...The stuff was useful...


Thinkfast 7 years ago

Thanks for the easily understandable helpful information =)


Erick Smart 7 years ago

Very usefull information, thanks a lot; but what is the best memory ram company?


Hal Licino profile image

Hal Licino 7 years ago from Toronto Author

The companies listed in the Hub are all excellent, but my last sticks of RAM came from OCZ. :)


abeerer profile image

abeerer 7 years ago from Earth

Many thanks, it really helped me to buy new pc, but how about laptop any advice on that?


Jawad UK  7 years ago

You always provide us a great informative resource. Thanks


Hal Licino profile image

Hal Licino 7 years ago from Toronto Author

abeerer, laptops generally utilize SODIMMs which although are structurally different, still have the same specifications as the desktop RAM.

Jawad UK, you're welcome! Thanks for the kind words!


najeeb k v 7 years ago

hi thanks gave this information


Hal Licino profile image

Hal Licino 7 years ago from Toronto Author

My pleasure! :)


Prashant 7 years ago

hey thanks for this very helpful blog buddy! it rokks!

and if somebody wana know about the ram in his system then he can go to crucial.com and then click "scan my system"

it will tell you everything bout your system memory. and then reference to this blog is icing on the cake!


Hal Licino profile image

Hal Licino 7 years ago from Toronto Author

Thanks, Prashant! Crucial has a great online test facility and I avail myself of it regularly.


issues veritas 7 years ago

Hal

Great info

Did you mean DDR2 in Mhz or Mbps

DDR2 400Mhz

DDR3 800Mbps

----------------------


Hal Licino profile image

Hal Licino 7 years ago from Toronto Author

Thanks, issues veritas for the heads up. I've edited that sentence to make it clearer and i've also updated it for the latest developments since it was written over a year and a half ago. DDR3 800Mbps RAM speed equals 400MHz data clock speed and now DDR3 has reached much higher speeds.


fttetv 7 years ago

THINK you're asking about how to find out what type of RAM your PC needs. Just run the free and superlative Crucial System Scanner tool at www.crucial.com. You'll get a full report as to the type of memory you need for your computer.


Hal Licino profile image

Hal Licino 7 years ago from Toronto Author

Yup. Crucial's scanner is excellent and there are various other similar tools avaliable on the net.


creativeMind profile image

creativeMind 7 years ago from Cochin

last year i replaced my motherboard and processor.. it was ddr2 compatible .. so i shifted to ddr2..now the system doesn't hang running huge memory applications..


Hal Licino profile image

Hal Licino 7 years ago from Toronto Author

DDR2 being faster than the plain vanilla DDR can show some remarkable improvements in performance, although I'm sure the total amount of RAM and your new CPU has a lot to do with it as well.


riyazul haq khan 7 years ago

hi a lot of thank to provide us knowledge about varius type of ram


Hal Licino profile image

Hal Licino 7 years ago from Toronto Author

Thanks!


Covert Hypnosis 1 7 years ago

Gee, I just bought a new computer and surely could have used this! But I think my DDR2 SDRAM was a good pick anyway.


Hal Licino profile image

Hal Licino 7 years ago from Toronto Author

What is your CPU and motherboard? Did you check it through an online scan utility like Crucial's?


Shahid 7 years ago

Hi SirWe are looking for 1GB DDR1 and 512GB DDR1 used rams in quantity 1000 each category asap. If you can kindly helps us and let us know the availability of the product.Tanking YouShahid (Director)0044 7957215215 (UK EURO TRADING LTD) ukeurotrading@yahoo.com


Hal Licino profile image

Hal Licino 7 years ago from Toronto Author

Er... dude... this isn't ebay... :(


IceCake 7 years ago

The type of ram your computer requires these days can be easily, and effortlessly, found out by using online scanning tools. "Crucial" is just one, out of the many websites available that offer this FREE service.

Just do a "Google" search for 'free online memory scan' if you want to find out about other websites that provide this service.


Hal Licino profile image

Hal Licino 7 years ago from Toronto Author

Yup. Already mentioned the crucial site in the comments 13 months ago! But thanks for the reminder to everyone anyway! :)


Kerala lottery results 7 years ago

DDR 2 can handle most applications pretty nicely..

haven't worked with ddr3 yet.

good post.


Hal Licino profile image

Hal Licino 7 years ago from Toronto Author

I've been running 12 GB of DDR3 for about nine months now and I absolutely could not be happier. Absolutely flawless!


kerala lottery results 6 years ago

regarding the size of RAM , i think 1 GB is enough ..with 2 gb the fragmentaion of RAM is high ..

so you need to defrag the RAM often.

iam shocked at Hal Licino comments as he mentioned 12 GB ram ..

is he running a server ??


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

I have 1 GB in a laptop running Vista Basic and after using it for five minutes I want to use it as a frisbee. You need to defrag the RAM often only if you're using MS-DOS 2.0. With Vista or 7 all of those functions are automatically handled by the OS. My main Core i7 920 runs 12 GB and I use each and every KB. I don't apply it as a server, only as a personal workstation for running Photoshop CS4 and dude, IT ROCKS! :)


nicomp profile image

nicomp 6 years ago from Ohio, USA

"ouble Data Rate interfaces provide two data transfers per differential clock."

What is a differential clock?


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

There is no short answer to the question, but the essence of it is included in the text of the Hub itself: "The data becomes registered when the CK goes high [the + side], and /CK goes low [the - side]." What that means in a nutshell is that the internal clock of the circuit gets two readings, one at the high end of the scale and another at the lower end. That's the difference in the "differential." The spread between these two readings, along with the actual measurement itself, allows the memory to synchronize properly. Hope that helps! :)


Kesterhu 6 years ago

I really appreciate the post.


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

You're very welcome!


pradeep chaurasia 6 years ago

pls discribe more.


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

What would you like to know? I'll be glad to assist.


Vandelay profile image

Vandelay 6 years ago from United States

Great Hub! 12 gigs of RAM, you must be 64bit or there is absolutely no point to it. Vista 32bit only supports 4GB of RAM, as does Windows 7 and XP. (XP actually maxes out at 2GB.) Please let your readers know that they cannot use DDR3 instead of DDR2 to improve performance. It will destroy their motherboards!


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

Vandelay, absolutely. I've always run 64 bit OSs on this puppy as 3.2 GB just doesn't do it. I was running Photoshop the other day and was using up 11.3 GB! That's a new record! And definitely: CHECK YOUR MOBO'S SPECS BEFORE CHANGING RAM DDRs!!!!!


Piyush Agarwal 6 years ago

Thanks alot this is wat i wan 2 know from many days thank again...


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

You're very welcome! :)


Eva Pazaitis 6 years ago

would to know where find if my toshiba laptop has ddr1 or ddrl 2 im confused dont where to find it

thanks Eva


vinu 6 years ago

why is ddr3 spelled as DDR3 SD ram ?

I saw the term DDR3 SDRAM today in an advertisemnt. How is it different from normal SD RAM ?


FB Siphon 6 years ago

Thanks for the table Its really great.


Confussed.. :( 6 years ago

I'hv a bit confusion..

wats the difference between "4GB (2 X 2 GB) 2 DIMM DDR3 1333Mhz" and "4GB (2GBx2) 1333MHz DDR3 SDRAM".

which is better and in what respect..


Quick Cash Concept 6 years ago

Thanks dude for providing such useful insight on DDR Rams. Can I use this article to submit to my teacher? ? :)


Sajjad 6 years ago

great job very helpful


radioactive43 6 years ago

Hi Hal Licino. I m a new user in Hub. I hav a question, it wud be better if u wud answer it quickly.

I bought a core i7-930 2.93GHz processor, an EVGA X58 4-way SLI motherboard (supports 24GB DDR3 RAMS), a 1TB HDD, an EVGA NVIDIA GTX 260- 896MB graphics card & a 850W PSU.

I didn't purchase any RAMs yet. Could u suggest me the minimum RAM specifications i hav to buy to make the above components work.


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

Sorry I haven't been answering for a while. So please feel free to submit this anywhere. radioactive43, you should have 3 or 6 or 9 or 12 or 18 or 24 GB RAM. Of course you're running a 64bit OS otherwise your only choice is 3GB. My suggestion would be to stick with 6 (3x2GB or 6x1GB), 12 (3x4GB or 6x2GB), or 24 (6x4GB). If you're on a tight budget and let's say you wanted to stick to Crucial, you could get 2GB modules CT945281, DDR3 PC3-8500 for under $50, but if you were thinking of mild to medium OCing, you might want to go with the more expensive CT945278, DDR3 PC3-12800 modules. 4GB sticks are still way more expensive per GB than the 2GBs, so it's all in your budget.


radioactive43 6 years ago

Ya i m using a 32bit OS. I will purchase within two days a Corsair 3 x 1GB - 1600Hz DDR3 RAMS. Will this be enough?

Do i also have to buy a cooler for these RAMS like Corsair AirFlow Pro?


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

Perfect buy. But don't waste your time on RAM coolers unless you're trying for liquid nitrogen OCs. :)


radioactive43 6 years ago

Thanks for the above suggestions. It was really helpful. But sorry, i have one more question.

One of my friends bought an EVGA P55 Classified 200 mother board, i7- 870 2.93GHz processor, Corsair 2 x 2GB DDR3 1600Hz RAM, one EVGA NVIDIA GTX 260 Core 216 graphics card.

But he is confused how much WATT power supply he will buy. Could u suggest the Brand (Thermaltake or Coolmax or Cougar) & minimum WATTAGE required for the above components to work?

The budget is bit tight, but feel free to suggest ur recommendations.


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

No problem. The GTX 260 Core 216 is going to draw 157 watts on idle and 262 on load. If he's only using one or two HDs he should be able to get along just fine with any good 550 watt and up power supply. For budget considerations, you can't go wrong with the Arctic Cooler Fusion 550R: Seasonic components and super quiet AC fan, and if you snoop around enough you'll find it at under $60. Hands down the best deal in a midrange power supply today. You can go with similar 550s from Thermaltake or Coolmax or Cougar, but you won't get the performance/dollar value of the AC Fusion 550R. :)


radioactive43 6 years ago

What type of Heat sinks can we both use for our systems?

For my friend, will the Themaltake V3 casing be enough?


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

The i7 870 runs pretty cool at stock, but I'd spend an extra few bucks and stick a 120mm fan just in the top vent of the V3. The top is really the best place to get some great airflow. Of course the Tuniq Tower 120 Extreme is the best around and my own personal favorite, but I've been running an Arctic Cooler Freezer 7 Pro V2 with a silent 3 speed 120mm fan to replace the standard (just strapped on with 2 rubber bands... works perfectly) and my i7 920 has never seen the high end of 55 C! :)


radioactive43 6 years ago

Thank u very much. One last question.

Can i use one GTX 260 Core 216 (896MB) superclocked graphics card as the main graphics card & one 9800GT (1024MB) as dedicated PhysX graphics card in an EVGA P55 Classified 200 motherboard?

And if i can use the both graphic cards together, would 750W PSU be enough?


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

I've never used the EVGA P55 Classified 200 but you should be fine, and a 750W will be more than enough.


radioactive43 6 years ago

Thank u very much. God bless u & ur knowledge. I may have more questions when i put all these components together. Till then no questions.


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

Thanks! Glad to help! Anytime! :)


faizi 6 years ago

Yeah good 1 ... but there should be a video that would better tell the differences of DIMMS and SIMMS


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

Sorry, I'm a dinosaur and I don't do video! :)


radioactive43 6 years ago

You will find the videos of DIMMs & SIMMs on Youtube, @ Faizi.

My pc is working like a monster. I bought everything watever u recommended. I m enjoying games like hell. Anyway thanks for ur help, @ Hal


Hal Licino profile image

Hal Licino 6 years ago from Toronto Author

Glad to be of help. :)

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