DDR questions...

Hey, I have no clue what all the different types of ram are so i need to ask a few questions.

My Ma's home computer has this motherboard:

http://www.asrock.com/mb/overview.asp?Model=K8NF6G-VSTA

It says it can take DDR400, But here are my questions:

1. I know there are different pin sizes(?) etc in some ram, So is DDR all 1 "type"? (Pins, Length etc)
2. What should i look for in the ram that decides if its good or bad? Someone said to check the "layers" Whats good and bad layers?

Thanks for any answers :)

Quote:

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Originally Posted by Luke_marlow

1. I know there are different pin sizes(?) etc in some ram, So is DDR all 1 "type"? (Pins, Length etc)
2. What should i look for in the ram that decides if its good or bad? Someone said to check the "layers" Whats good and bad layers?

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All DDR 1 is physically interchangable.

Look for low latencies...i.e., 2,3,3,5, etc.
The lower the numbers, the better.

It'll be 184 pin RAM.

Ok, Got that covered, So heres a problem related with ram for my computer. I was running on 768MB ram, But today my 2x 1GB sticks came. (I said in a previous thread i had 2GB, As i knew they were coming, So asking for updates on what i would have had when parts arrive)

Anyway, My motherboard can only take 1GB sticks in the 2 slots (2 GB total) However, Once i added them in, They dont work.

By not working, I mean the computer starts ok, Sounds like its running fine, But no signal gets to the monitor.

All the ram sticks are 400 Mhz (1GB * 2 / 512mb * 1 / 256mb * 1) Below is what combinations i tried:

Slot 1: 1GB
Slot 2: None
Result: Screen wont load.

Slot 1: 1GB
Slot 2: 1GB
Result: Same as above.

Slot 1: 1GB
Slot 2: 512MB
Result: Starts fine, Windows starts, But when i check current memory in the spec display screen, It only lists 512MB and not the 1GB.

Anyone ever had this issue?
Could something in my system be blocking anything above X amount in a slot? (Windows XP / SP2)

Edit: The board is P4i65G which states on the page:

Quote:

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Memory
- Dual Channel DDR memory technology
- 2 x DDR DIMM slots
- Supports DDR400/333/266
- Max. capacity: 2GB

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Did you check the mobo brand site for compatible sticks? I'd do so now.

What processor do you have?

If it has a 533MHz FSB then the system will only support DDR266 and DDR333 memory. See page 8 of the manual. You may be able to get round that by forcing the memory speed in bios (page 24).

The processor is a crappy celeron 2.66Ghz which allows upto DDR400 i believe, Which is what the memory was.

It turned out to be a good thing though, Kinda. The ram didn`t work in mine, But i took it to the parents house and tried in their board and it works fine in there. So at least i have the initial post all sorted now.

Only difference between my comp and theirs (to me) is that mines intel and theirs is AMD, But im clueless with all the specs etc, Although trying to learn more about it all :)

Just to find one that works for mine now. Is www.crucial.com memory reliable and good quality? Considering going there as it looks simple enough. Select maker, select model and get a list of what will work etc.

Belarc advisor will tell you your mobo.

The 2.66GHz Celeron has an FSB speed of 533MHz, so there's absolutely no benefit in fitting DDR400 memory instead of DDR333 and you run the risk that you won't be able to get it to post. That may be what happened with the 2x1GB sticks you tried previously.

Normally I would suggest buying the fastest memory within your budget, just so you can move it on to another system if necessary. But since newer systems won't accept DDR 1 memory there doesn't seem much point.
This should meet your requirements.
http://www.crucial.com/store/partspe...T2KIT12864Z335

I'd be interested to know the maker of the original sticks you tried though, I've seen some comments about compatibility problems of the type you describe with Kingston DDR400 memory. It's a shame AsRock don't provide a memory compatibility list.

Quote:

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Originally Posted by lynx

I'd be interested to know the maker of the original sticks you tried though, I've seen some comments about compatibility problems of the type you describe with Kingston DDR400 memory. It's a shame AsRock don't provide a memory compatibility list.

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I have no clue what make they were, They didn`t have one stated on....wait for it....ebay :O

They didnt really cost alot anyway, Around $60-70 for the 2 gig, But i chose some of the cheapest because i was thinking of if they would work or not anyway. I seen others listed on there that only worked with certain chipsets etc, So i always had doubts that they wouldnt work, Which turned out to be correct.

At least some good came of it and one problem got fixed while another occurred :lol:

Could you tell me what would be the difference between the 2GB that crucial says is best for the mobo when i select the motherboard etc in the menu or the one you pointed out.

They are both the same price and i was thinking about getting what crucial suggested, But if it will cause any problems etc i would just go with the PC2700.

Differences:
DDR400 - 2.6v, CL3
DDR333 - 2.5v, CL2.5

Does your mobo support 2.6v memory (it probably does, but you need to be sure). The problem here is that the Asrock board only has 3 settings, low, high and auto. You can bet that since there aren't any other options then the auto only switches between low and high. That should be fine for 2.5v memory (low will certainly be 2.5v), but there's nothing to indicate what high actually is, nor when it switches from low to high if set to auto.

The other difference is the CAS Latency, but that's relative to the clock rate. If you recalculate that as actual elapsed time you get:
CL3 @ DDR400 = 3 / (200 * 10^6) = 15ns
CL2.5 @ DDR333 = 2.5 / (167 * 10^6) = 15ns

As you can see it is exactly the same in terms of actual time. With your FSB it will only handle DDR333 rate maximum, so the SPD chip would probably compensate and allow DDR400 memory to use CL2.5 if running as DDR333, in which case there would be no benefit. However, if the SPD chip does not compensate then the DDR400 memory running as DDR333 would actually perform worse. You could probably regain the performance by setting the timings manually, but would you know what all the settings needed to be?

The DDR400 memory will probably work fine, but since there is no benefit and may even perform worse I don't see the point in taking the risk.