BREAKING THE PC-100 LABEL CODE

[Roy]

Every PC-100 module must bear a sticker that reads PC-100 abc-dxy where a,b,c,d,x,&y are numbers.

Here are what they mean, -/- their possible values, and -/- some notes.

a - CAS Latency (CL), in clock cycles -/- 2 (better) or 3 (standard)

b - RAS-to-CAS delay (tRCD), in clock cycles -/- 2 (better) or 3 (worst)

c - RAS precharge time (tRP), in clock cycles -/- 2 (better) or 3 (worst)

d - Time for valid output to appear after clock setup (tAC), in nanoseconds (ns) -/- 6 (standard) or 7 (ONLY with 1 or 2 DIMMS. 3 or more REQUIRE 6ns tAC.)

x - SDP EEPROM protocol version -/- typically 2 -/- 2 means version 1.2

y - reserved -/- 0 -/- Future apps. All current DIMMs should be 0

Also, - Clock Period (tCLK), in ns -/- 8 (better) or 10 (standard)

So now you know!

Special thanks to c't magazine.

[This message has been edited by Roy (edited 02-12-99).]

[Isos]

No one told me that before. Thank you.

[Roy]

The best chips right now are 2-2-2 / 6-2-0

[Roy]

(ignore this)

[ZX1100]

It's not nice to raise your Personal posts to the Top unless you have something new to Add. lol, Jim

[Maxx]

man this really sucks that means i'm gonna have to open my case again. whats that 12 times this month i really should get one of those swing open cases........

[JP]

Maxx-
Do as I do and just leave the case off. Saves lots of time. And I just love to be able to feel how hot my CPU is!
-JP
http://members.xoom.com/PSComputers

[JP]

I am holding in my hand SDRAM that has no PC100 lable but it does say PC100 on each chip. I don't see the numbers that Roy wrote about. Is this PC100 RAM?(I did not ask for PC100 when I bought it)
-JP
http://members.xoom.com/PSComputers

[bighammer]

his numbers refer to a sticker on the module.
Read and post what the #s on the chips are, they should all have the same number{or close]

[spdsk8r]

JP -

If there's no sticker on it, then chances are it's only SDRAM. Does it have a 10 alone somewhere on one of the chips? That would probably mean it's 10ns SDRAM. You can still push about 100Mhz. out of it... Sometimes 112Mhz. if you're lucky

[Roy]

I have some "premium" SDRAM from before the PC-100 specs were written. It was supposed to work at 100.

It's solid at 112!

jp - post all the letters and numbers on an individual chip and I'll check my charts.

[bighammer]

myself also.

[hoang201]

OK 2 have two PC 100 that I want to identify
they got all kind of number but the ones that
post in label code
Here are the numbers for the 64 Meg:
MA-481222 8X64 PC100
P8M648Y-100 CLSA 9850/N1389
Spectec Usa Y4 0849 524LKT -8A

And these are number of the 128 Meg
SEC KOREA 810 PC100
KM4858030BT-G8 SD16V72
VSL461KB
(Paper sticker label have this nr 9820731
6039802 and the antistatic bag have this nr:
98425003)...TIA...HN

[Roy]

hoang201 - The 128 is Samsung (SEC) rated as CL2 up to 100MHz and CL3 at 112 and 125MHz.

I am not able to find information about the 64 (Spectec?). However, the "-8A" suggests it is of similar quality.

[JP]

Here's what's written on my SDRAM chips:
Musa
AC57S168010-7
PC-100
Tiwan 9843

-JP
http://members.xoom.com/PSComputers