memory info>

[atc_traffic856]

I just finish building a P11 PC and only had 32M memory to install.
My mother board has 3 slots, and runs 66MHZ I look for more memory to install, trying to bring it up to aleast 256MB
After i search the necessary criteria for memory, it related the following terms for a 128 168 pin dimm /100 which it will take but there are some terms that I do not understand as per eg. PC100/16
I do not understand the number 16, is this the density factor of the memory module? Non ECC what is that refering too? CAS 3? LATENCY 8C
The latency is this the wait period for the memory to reset itself?

[gwallen4]

I think 16 is the speed - 16 nanosec.

[Budfred]

16 nanoseconds would be extremely fast RAM, I don't think even new RAM is that fast. I think fast RAM runs about 60 nanoseconds. I suspect the number represents the number of chip banks, but not sure about that.

[rond36]

ECC stands for "error correcting code." If you have a single-bit memory error, ECC memory will detect and correct the error. If you have a double-bit memory error, ECC memory will detect and report the error.
Not all motherboards can use ECC memory and you can't mix ECC and non ECC modules on any board.
The way to tell if you have ECC modules installed is to count the number of chips on the DIMM and divide by 8 if it doesn't come out even it is an ECC DIMM

PC66 is 10ns
PC100 is 8ns
And it keeps getting faster from there.
PC2100 is 7.5ns
PC2700 is 6ns
PC3200 is 4ns

Another thing to watch out for is the clock timing of the RAM!
2-clock SDRAM was the first generation of SDRAM that used 2 CK, or Clock lines, to synchronize the memory chips with the motherboard. Systems that require 2-clock SDRAM won't accept 4- clock SDRAM and vice versa.

All PC66 SDRAM is 2 clock
PC100 can be 2 clock or 4 clock
Most P II motherboards can only use 2 clock PC100

I ran into this problem upgrading a P II 333Mhz computer with a DFI motherboard. When I installed the new RAM the system only counted half of it.

I think your best bet would be to go to Crucial's (http://www.crucial.com/store/listmfgr.asp?cat=RAM) web site and use their RAM selector to find SDRAM for your system.

[atc_traffic856]

Yes you are right. Although I did a memory search for this system and they related about a Density factor, in which I assume is the density of the pins. The CL is the CAS latency, and that my board is a CL 3 which is slower then the 2 etc. But is this the clock cycle for Once Command is given it takes that amount of cycles to give the Information?

[Budfred]

Wow, if those speeds are correct, I am really behind the times for RAM speed. Last time I paid any serious attention to it RAM speeds were running more like 60ns for fast RAM and I didn't think they have improved it that much!:eek:

[ranchdog]

I'm using Twinmoss\Winbond DDR PC3700

that is 5ns. Have some 3200 that is 4ns.

RAM Timings are set at 4-2-2-2 in Bios.

And yes it's fast.



RD.

[saphalline]

The CL is the CAS latency, and that my board is a CL 3 which is slower then the 2 etc. But is this the clock cycle for Once Command is given it takes that amount of cycles to give the Information?Sort of... RAM may be about a million times faster than the hard drive, but it's still dog-slow to the CPU. When the CPU needs data in RAM, it takes quite awhile for the RAM to deliver it!

First, the correct row needs to be "charged", to prepare that specific row for data transfer, which takes a few clock cycles - RAS. Then the correct collumn needs to be charged, which takes a bit longer (due to SDRAM architecture) - CAS. Now in between there is the RAS-to-CAS pre-charge delay, and various other timings afterwards, but that's the basics of what happens.

And the part that takes the longest out of all of those? CAS - which is why a lower CAS is generally better, but anything lower than 2 isn't worth it. Yet...

[rio_bugarin]

dont know where i find this site. i think i found it somewhere here in the forums

http://www.simmtester.com/