Memory: CAS latency. How do I tell?

[Oscarfish]

Hi all,

Is there a shareware utility out there os something that will be able to tell me what CAS latency my 256mb (2*128mb) PC100 168-pin DIMMs have? The vendor I bought it from said it was CAS 2, but I'd like to be sure...

Thanks http://www.sysopt.com/forum/smile.gif


Ryan Yadsko
http://www.oscarfish.com

[Roy]

If it bears a PC-100 label (PC100 ### ###), the third number is CAS Latency.

Oops! The first number is CL. - Roy

Try the chip maker's web site for detailed data, or post all of the numbers on an individual chip, and I'll see if my records shed any light.

[This message has been edited by Roy (edited 05-06-99).]

[DavidX]

Roy
Please see my "PC100 label" post in "Technical Support". I was asking this very question. Perhaps you could shed some light on these labels?

[Oscarfish]

Hi again,

Here's what's physically on each of the modules:

9914
MT
TG
1-1 (or I-I, can't tell)
48LC8M8A2
-8E B

Here's what Sandra tells me in Logical/Chipset Memory Banks:

Smart Modular PDC16UV7284B103TSy (last digit "y" has two dots over it)
D730C029 128MB SDRAM CAS3 PC100-322-622

Physical/BIOS Memory Banks tell me:

128MB 7ns DIMM SDRAM single-bank

I went by Micron's (The MT) website, although I can't find 128mb SDRAM with the serial/model number that's on the modules. From what Sanda told me, though, it looks like I have CAS 3. What do you think?

[Roy]

From what I can find, the -8E makes it 125MHz RAM, CL3 @ 125, CL2 @ 100. http://www.sysopt.com/forum/smile.gif

The six numbers on the label are:

1 - CAS Latency CL in clock cycles.
2 - RAS-to-CAS Delay tRCD in clock cycles.
3 - RAS Precharge time tRP in clock cycles.
4 - Time for valid output to appear after clock setup tAC in nanoseconds.
5 - SPD EEPROM protocol version (usually 2).
6 - Reserved, should be 0.

[This message has been edited by Roy (edited 05-06-99).]

[Oscarfish]

Hi Roy,

Thanks for your information - basically, if I run it at 100mhz or less, it's CAS 2, but if I run it 125mhz (or perhaps over 100mhz), it's CAS 3?

Thanks http://www.sysopt.com/forum/smile.gif


Ryan Yadsko
http://www.oscarfish.com

[Roy]

Yup. You can try CL2 at the higher speeds, sometimes it works. The performance difference is minor, buying CL2 PC100 is just a way of being sure you're getting good RAM.