Question 'bout CAS latency??

[danger55]

Hi

 

I have 3 RAM sticks installed, all different brands but all PC3200. One is a 512M Kingmax SuperRam and others are 256M HTL and 256M Hynix. They all appear to have different timings but can I adjust CAS latency according to the RAM with tightest timings (which is the Kingmax)?? and whats the worse that can happen?Also if this just causes instability, should I just bump the settings up a bit 'til it starts to like it?

[Clay]

Humm I believe it's probably best to set those to the spd values of the loosest stick. Then try to tighten them down(It may. or may not work. Most likely not) Also some cas-2 memories won't work very well at cas 2.5 or 3. And vica'-versa' but I'd try loosest first then tighten them hopefully find some happy medium if possible. I dunno jus' my best guess. Good luck "Clay"

[danger55]

Thanks Clay- I'll have a go.

Also this is obviously a bit new to me but a question about the timing numbers...

I understand when 3 numbers are quoted eg. 2.5-3-3, which are CAS, tRP and tRCD (correct me if I'm wrong!) but what is the 4th number that is sometimes quoted? Is it the 3 numbers that are the important ones???

[dr_bowtie]

All the timing numbers are important....especially is you run into problems that are memory related.....

 

On the NF2 boards it is very easy to scramble you bios...making it nonbootable by tightening your timings....or loosening them... be prepared with a backup plan if it happens..

[kitfit1]

I notice from your sig Danger55 that your mobo uses the ViaKT400 chipset. I don't know if you are thinking about trying to run at 200fsb but if you are, resist the temptation. You hav'nt got a working pci/agp lock with that chipset and the result will be corrupted hard drives. As Clay said a starting point would be at the timings of your slowest stick and slowly work your up.

[medianOCer]

Yeah, good point kitfit1. The 200/400 FSB on that board could be a no go, or may

cause problems, especially with trying to run more than one or two RAM sticks in there.

 

danger55,

I think the number you are referring to would be the tRAS memory timing. Commonly

you'll see the 'basic' memory timings represented as tRAS, tRCD, tRP and tCL (or CAS).

They are all important and can vary quite a bit from one brand of RAM chip to another.

They can also vary from one RAM chip die to another, or possibly even from batch to batch

of the same type of RAM chip die.

 

An example of the 'basic' timings, as you indicated, would be (x)-3-3-2.5, with (x) being

more of a variable and depending on what the RAM, Chipset and CPU of an MB would prefer

for smooth running and best stability. Those are the main ones which many motherboards will

have available for a user to change. Depending on the board, and the BIOS, there can be

many more that would be accessible also.