DDR/General Memory FAQ (2003)

[TwoRails]

Thanks for the update on CPUID, Spyda!!

[Spyda]

its a bit iffy though, although nothing serious, with my memory it tells me its running at the 5:4 divider at 160Mhz, when its actually 1:1 at 200Mhz.
although when at 5:4 or 3:2 it calculates correctly, so watch out for changes that dont match the BIOS

[ComputerDragon79]

I just brought a dual channel DDR board and it says in the manual that the chips must be same type and density. I know what density means from reading the FAQ but what does it mean when it refers to type?

[PCNUBY]

sorry if anyone's asked this, but which is better: memory with a higher frequency or memory with a lower CL rating? And what difference does a lower or higher CL rating make?

[Spyda]

its sort of a mixture of both, a higher frequency and a lower CAS rating are desireable.

if the RAM was the same speed, say DDR333 go with the lower CAS.

if it was between DDR333 CAS2 and DDR434 CAS2.5, id still go with the DDR434 as it has a 100Mhz advantage over the lower CAS DDR333.

[ThaKid]

When checking out a motherboard how do you know what kind of memory to get for it?

Does it actually tell you somewhere on the specs of the motherboard?

Thank you.

[TwoRails]

Yes. Not only in the ower's manual, but there is a ton of online info, too!

[Spyda]

its usually plastered all over the box too

[KayGee1028]

yea, but if you buy a piece of crap motherboard then the manual will probly not help cuz itll probly be written in some Taiwanese or English that a 5 year old would write

[marlowe]

if you want to use the DDR function you must have two identical sticks of memory in the main slots. On the newer boards, there are 4 slots. usually they are color coded. If color coded, be sure to fill all color slots with the same sticks. Slot one and three are matched. Slot two and four are matched. Install the two sticks in slot one and three and you use DDR. Install the sticks in slot one two and three and you use Single.

[Spyda]

not always the case, some have 3 where there is a master slot on its own and 2 others can be populated however you want

[Jester]

what is everyones opinion of Geil brand RAM

[Ogredemir]

so if DC only works with 2 matched sticks of ram how does the third one come into play if you want it? say i buy the corsair twinx512mb XMS memory. do they sell that in single sticks? if so, and i use 3, will it just be a waste of money or willl it still enhance my system reasonably?

[Cricket]

Originally posted by Radioactiveninja what is everyones opinion of Geil brand RAM

I started using Geil RAM recently and haven't had any problems with it in INTEL and AMD builds. Seems like good stuff to me.

Cricket

[Spyda]

Geil golden dragon RAM absolutely storms

[Deathchant]

Hi people

My kingston memory has the following latencies: 2-2-2-6-1
the first number is CAS, 2nd is RAS to CAS delay, 3rd is RAS precharge, 4th is tRAS, 5th is CMD.

I have a P4C800Deluxe mobo and I can set these latencies manually in the BIOS. The first 3 of the latency numbers are no problem, but the last 2 numbers are called differently in my BIOS: tRAS en CMS aren't there, but there are: DRAM Precharge Delay (standard on 8, 6 or 4 clocks)

and DRAM burst length (standard op 8 clocks, i can choose 8 or 6)

Is the tRAS the same as DRAM Precharge delay in my BIOS?

Does anyone know how to set this latencies 2-2-2-6-1 ?
BTW: the last number is 1, but I cannot choose 1 for any latency......

Greets,

[Aaaron]

i read something about sd ram single sided and double sided it doesn't apply much but could someone explain about it

[ceh4702]

You have to watch for the hidden stuff in a manual. Often you can only use 2 out of 3 slots for DDR400 or some such silly thing.

[EvErY_DaY]

good post

[mattg2k4]

I'm curious since my next computer will contain a dual-DDR capable motherboard, suppose I use two sticks of 512MB, will my system have access to just 512MB or to 1024MB?

In other words, is this like striped raid drives where you only get half of the capacity or is it something else?

[Karnevil9]

No, it will have the full adavntage of the 1024mb. In theory it is suppose to doulble the performance so it would run as if you had 2048mb. In reality you only get a 5% to 20% peformance boost.

[Floppyman]

CAS latency or Read latency: In other words, CAS Latency is the ratio of the memory's column access time divided by the current system clock. The column access time turns out to be a constant value, so you can see as you in increase the system clock it becomes harder to achieve a lower CAS latency (denominator grows-- numerator stays the same-- you get the idea). From this and the example up above you can conclude that the lower the CAS delay or latency, the better.

Correction:

The denominator does not grow, it becomes smaller instead. The CAS latency is actually the ratio of the column access time divided by the clock cycle time (not the system clock). As you increase your system clock or bus, this value (clock cycle time) would decrease, making harder to achieve a lower CAS latency.

Sorry for the mixup.

Information for this I got from here:
http://www.cybertechhelp.com/html/tu...rial.php/id/61

[Joeberg]

Thanks for the clarification

[darksilverazn]

Which is better DDR 266 or 333? I use my computer for word processing, AIM, surfing & normal multimedia stuff like Digital pix & maybe some video in the near future.

[Floppyman]

What motherboard and cpu are you using or planning to use? HTH

[Karnevil9]

If you are going to do video work then you should go with the highest MHZ your motherboard will support. If you have a 266mhz top rated mobo for it's memory then running 333mhz memory won't do you any good as it will run at the lower speed anyway. If it is rated at 333mhz then go with that. To get the full advantage of your moherboard, run the CPU and Memory at the highest value that it supprts for each.

[jr.delgiorno]

Im building a new system. The mobo is a ASUS P4C800-E Deluxe, which supports dual DDR memory up to 4GB. What runs better? (2) 512MB DDR PC3200 in slot 1 & 3 or (4) 512MB DDR PC3200 in all of the slots?

[Karnevil9]

The four sticks of 512mb would be better. You're really not going to double the performance by using the Double channel fucntion. In actual practice it only improves performance by about 5 to 20 percent. But you would be better buying two 512mb Pc3200 sticks of ram and using the dual channel function then usuing lets say one stick of 1 gig ram and not using it, or two 512mbs sticks and putting them in the memory slots that wouldn't activate it. In reality two sticks of the 512mb should be more than enough.

[Riddler]

does anyone know about DDR2
Is DDR2 the same thing as dual ddr

[Maizster]

Hellooo...
What could be the reason of RAM starting to count a lot slowlier than previously when starting up? I added new 256MB to my 128MB and now it counts more slowly than it did... It's a little bit frustrating...