# RAM Timing Explained



## NoAffinity

Good stuff, bind. I edited in another "copied from" at the beginning of the excerpt, just so nobody comes here screaming plagiarism. Very useful info, tho.


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## zokus

Good find, good job. It's exactly what I would have wanted if I were a noob too lazy to find my manual.


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## TwEaK_MoNkeY

yeah thanx for the self esteem boost zokus








but that was a great help now some one needs to explain to me memory ratios???????????? thanx


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## AndrewBEJ

I want to ask,my mb support ddr 533,what if i use ddr2 667 ,will it works? thanks for the help


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## Bindusar

Yes, it will just run at the lower FSB speed.


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## AndrewBEJ

ok,thanks mate.


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## iwannaplaygames

Quote:


Originally Posted by *zokus*
Good find, good job. It's exactly what I would have wanted if I were a noob too lazy to find my manual.

i got my manual on my lap and its witten by a 4th grade dropout. "this setting adjusts the CAS latencie"







great, thanks for repeating what the BOIS says.

_NOW_ i know what CAS latencie is, man am i tired of that chick yelling at me
"system failed doto CPU overclocking" good find man


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## Strider_2001

How do I go about changing my mem timings...Would that be done in my CMOS???Or through software...Please help....Uber NOOB here when it comes to overclocking...Thanks in advance


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## SoFaKiNgHiGh

Quote:


Originally Posted by *Strider_2001*
How do I go about changing my mem timings...Would that be done in my CMOS???Or through software...Please help....Uber NOOB here when it comes to overclocking...Thanks in advance

usually in ur advanced BIOS options


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## Strider_2001

Any recommended settings to start with???


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## SoFaKiNgHiGh

well i got mine at 2-3-3-10....but P4's are different i've heard they perfer higher FSB than tighter timings...all i can say is stick around on here till someone who knows more than me can help ya


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## Strider_2001

If I get my timings off can I do any damage to my mem or will the performance just be bad???


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## aznchowboy650

lowering timings will not harm ram infact it might give teh ram a lil more living time hte rreasons ppl lower their timings is that they want to overclock more


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## Frost

This is a very helpful guide. More of a neutral guide then a "intel specific" guide. May I suggest adding this to the amd memory forum. I know for me atleast, having an AMD I never thought twice to look through the intel forum sections. This guide is something I was missing, it helps for either brand. I just think more newer people, who don't have intel would notice this helpful guide if it is in the amd forums as well.


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## AMD-rules

What would be faster??

200mhz (Divider) at 2-2-2-6
or
266mhz(divider) at 2.5-3-3-6


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## Burn

Only benchmarks will tell. Use Sisoft Sandra's Memory Bandwidth benchmark to find out which is faster.


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## Firefox22

Yo this may be a little off top but on an memory band test by SiSoftware Sandra 2005. It`s telling me that I have low band. test show 47% efficency.
Any Ideas on how to fix this.


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## tiwas

Ok, I've got a question here...I've found my max overclock (367 orthos stable) and now I'd like to tighten my ram timings a bit (running them 4:5). They're rated [email protected] so there should be loads of headroom (http://www.corsairmemory.com/corsair...8-8500C5D.pdf).

Now, first of all I couldn't find ""RAS activate to precharge" or "DRAM write recovery time" in the guide. Guess ASUS just uses different names for them.

So, my questions are as follows:
1. CAS latency is the most important, right? Should I lower this as much as possible until the memory tests (memtest86) starts failing and then up one notch before working on the others?
2. Will memtest fail if I go overboard, or will the computer only be more unstable?
3. Should all of these values be lowered as much as possible, or is there any that would benefit from being kept stock or even increased?

Thanks for a good thread!


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## johnsrg

You know what would be really helpful.....BIOS screen shots of overclocked memory settings for different motherboards. Because each motherbord BIOS has different configurations.....This is what I want for XMAS

number of motherboards I have destroyed during overclocking experiments (while using forum instructions) = 2

Getting expensive....


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## Choggs396

cool, I always wondered exactly what those timings meant. Thanks!


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## this n00b again

well now i know what they mean how do i choose the #'s

i guess this would be the right place to post this

i have a pc:

E6600
Msi p6n sli - fi
Geforce 6600
ocz2p8002gk -> 2 gigs of dual channel ddr2- 800
http://www.ocztechnology.com/product...m_dual_channel
on x64 vista.

well it was working fine until i put in:
http://www.ocztechnology.com/product...module_2gb_kit

now the PC has slowed down majorily. takes for ever to load vista and i tried to i nstall cpu z id but its so slow i can't even install it. when i look at the cpu useage, its stuck at 100%

now im a n00b but im willing to bet this has something to do with the memory timings, right now its set to auto, because it was always set to auto and it worked fine.

it says they should both operate at 2.1 volts
the platnium ram timings are CL 4-5-4-15 (CAS-TRCD-TRP-TRAS)
and the vista upgrade tiimings are CL 5-5-5-15 (CAS-TRCD-TRP-TRAS)

now since its probably because of the ram and its set on auto in bios, i can change to manual, but what should i put in for the number when i put in manual timings?

also when i put in the manual timings, there are about like 10 other numbers that i dont have the digits to because in manual mode alot of settings come up but i only have 4 numbers. so w hat should i do about those? should i just leave those the default numbers?

thanks in advance! hehe


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## apvm

A little confuse here after reading this...my max fsb is 320mhz and I have DDR2-800, I am running ram at 10:8 which is exactly 800, 1:1 means 640, so should I set it back to 640 for 1:1 ? Tia


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## drjoey1500

cool


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## CesarWilkins

Cas 3 is the safe, I had a mix of cas2.5 512 and cas3 512 both running at ddr400 and cas2.5 for more than 2 years, the cas3 got bad, later i paired the cas2.5vdata ram whit a cas2.5 kingston and they worked like dual channel


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## Llarion

Great explanations, thanks!!


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## Acroma

so, when some one states the ram runs at 5-5-5-18. What do each # stand for, because i have alot more settings then just the 4 in the bios.

Thanks in advance, +rep to whoever can help^.^

Edit*
Also i am Using A-data ram, and would like to know the limit of these settings and if i have to change anything els if i change those settings.


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## NMA3

what would you ppl recommend me to do!
run my ddr3 @ 1066 with 7 7 7 21 timings
pr run it @ 1333 with 9 9 9 24 timings , it is corsair ddr3 working ant 1.7 volts,
and how much i can push the timings @ 1333 mhz?
THX A LOT!


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## vetta2000

I was going to ask, but i found out the answer on kingston's site so i figured I'd share...this has been bugging me lately because I didnt know what each number represented:

Quote:

The information below will help illustrate the appropriate settings when adjusting the memory timings in the motherboard BIOS for optimum performance. Please note that these settings may vary depending on motherboard make/model or BIOS update.

Sample:

Part NumberTimings
KHX3200A/5122-3-2-6-1

TimingDefinitionAbbreviationsWhat it does

2CAS LatencyCLDelay between activation of row and reading of row

3RAS to CAS (or Row to Column Delay)tRCDActivates row

2Row Precharge Delay (or RAS Precharge Delay)tRP/tRCP Deactivates row

6Row Active Delay (or RAS Active Delay, or time to ready)tRA/tRD/tRASNumber of clock cycles between activation and deactivation of row

1Command RateCMD RateDelay between chip select and command

I am going to take a guess and say that if there are settings that you dont see here you should just leave them on auto, and only set what you know.


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## 18 is # 1

*2x2GB* Powerchips need a tRFC of 50-65
This includes most of the 2x2GB kits on the market.


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## Kasper

This is what my timings look like set to auto in the BIOS. I think this is best on my mobo to leave those on the recommended settings for a stable oc


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## Cicuta

hello!

My memory says 5-5-5-15 when i open my case this morning and when i use CPU-Z it says 5-5-5-18 i think it is wrong.
How can i do to set it to 5-5-5-15?
my bios dosent let me set it... Should I update my bios or Flashimg my bios?
I've never did it before.


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## TRELOXELO

thank u man


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## Ecchi-BANZAII!!!

*Casting level 3 Necro on this thread*

I think it's about time manufactors should give us the WHOLE timing chart.
I hate when using Intel Motherboards (the brand (like EVGA, ASUS, MSI etc)) because they can't have the other timings on auto when having the CL5-5-5-15 timings on manual.









What would be the stock timings (complete list) for 2x2GB C5D Dominator 1066MHz besides the standard CL5-5-5-15?


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## Clockadile Dundee

Quote:


Originally Posted by *Ecchi-BANZAII!!!* 
*Casting level 3 Necro on this thread*

I think it's about time manufactors should give us the WHOLE timing chart.
I hate when using Intel Motherboards (the brand (like EVGA, ASUS, MSI etc)) because they can't have the other timings on auto when having the CL5-5-5-15 timings on manual.









What would be the stock timings (complete list) for 2x2GB C5D Dominator 1066MHz besides the standard CL5-5-5-15?

I'm sure you weren't referring to the Classified, but I have what seems like about 40 different memory timing settings. Do you know where I could find what all of these are, and what the appropriate methodology is, for fine-tuning something like that?


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## Roger Bertrand

Great to have a knowledgable colleague that can explain these matters Crystal Clear.
Thanks a lot for your contribution to my Daily Learnings! This made it to my Personal Encyclopedia of Universal Knowledge!
Have a fantastic Day!
Roger


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## SpcCdr

holy thread necro
Roger,








Welcome to OCN









If you think the above is worthy of bookmarkification:
Read these for more RAM information than you can absorb in one sitting:

*The Secrets of Memory*
Part 1 The Basics
Part 2 Compact DDR Form factors
Part 3 Memory Generations Explained: Architecture & inner workings. (DDR -vs- DDR2 -vs- DDR3)
&
Part 4 DDR3: Memory for a New Generation

Cheers ALL


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## appless

i got a lappy that already comes with 4gb of ddr 3 (2 dim) ram running at 1066 6-6-6-15 and my lil bro bought a 4gb ddr 3 at 1066 with 7-7-7-20 (single dim)i was wondering would it be possible to install the 4gb single dim to make 6gb or do i need to configure some stuff? or the mb will auto fix the latency and other things which i have no idea about??









thanks


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## Arnie'

Great Guide, helped me out alot. thanks


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## SteveMcQueen

It should be added in OP that ECC correctly explained stands for error-correcting code, whereas the ecc-method is error checking and correction. It leads to misunderstanding.


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## WakaFlockaFlam2

so why do RAM timings keep getting slower? in this article it mentions 2-2-2 timing, but currently all high performance RAM is 9-9-9 or higher?


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## FtW 420

Quote:


> Originally Posted by *WakaFlockaFlam2*
> 
> so why do RAM timings keep getting slower? in this article it mentions 2-2-2 timing, but currently all high performance RAM is 9-9-9 or higher?


As memory speeds are getting faster the timings are loosening, with the newer platforms the frequency is making more difference to performance than the tighter timings. Running the timings as tight as possible still helps at a given frequency, but getting to the higher frequency has more impact.
Some of the older kits with decent timings still work well on the newer platforms though.


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