JP1: DRAM Voltage Jumper..

[ghosty]

I was just setting up a new comp using a pcwave board.. the M925ALMU. Now I bought 256 MB PC2100 DDR ram.. It works fine I have it in the DDR slots. But my question is about the JP1 Jumper.. the DRAM Voltage Jumper. It says 2.5V(DDR) is "Open Pins 1-2" does this mean to have the jumper connector (that tiny plastic thing) off the pins? Or am I interperting OPEN the wrong way. It goes on to say 3V (SDR) is "Short Pins 1-2". Anyways I am confused about the meaning of "Open" and "Short". I want to make sure the ram is working properly and at Speed.

Now if someone could also answer this question too:
when looking at DDR SDRAM they are marked as PCxxxx. The xxxx stands for the MBps, bandwidth.. not the speed at which they run.. the MHz.. I am wondering how I can tell what speed the DDR runs at.. so how would I find out what PC2100 runs at?

Thanks alot!

 

[ghosty]

bump

 

[jjyiz28]

Originally posted by: ghosty
I was just setting up a new comp using a pcwave board.. the M925ALMU. Now I bought 256 MB PC2100 DDR ram.. It works fine I have it in the DDR slots. But my question is about the JP1 Jumper.. the DRAM Voltage Jumper. It says 2.5V(DDR) is "Open Pins 1-2" does this mean to have the jumper connector (that tiny plastic thing) off the pins? Or am I interperting OPEN the wrong way. It goes on to say 3V (SDR) is "Short Pins 1-2". Anyways I am confused about the meaning of "Open" and "Short". I want to make sure the ram is working properly and at Speed.

Now if someone could also answer this question too:
when looking at DDR SDRAM they are marked as PCxxxx. The xxxx stands for the MBps, bandwidth.. not the speed at which they run.. the MHz.. I am wondering how I can tell what speed the DDR runs at.. so how would I find out what PC2100 runs at?

Thanks alot!

open, unshunted, unshorted means the same thing. do not put the jumper

close, shunted, short, means the same thing. put on the jumper

therefore since u have ddr, do NOT put the jumper on the pins 1-2.


ur 2nd question.
the core speed of a pc2100 is 133mhz. since it transfers 2 bits per cycle, it is effectively 266mhz. now since all pentiums and its equivalent and up has a 64 bit external bus, 64 bits equaling 8 bytes. do a little math and multiply 266mhz to 8 bytes, and you get 2100 mb per second.

 

[ghosty]

Great info jjyiz28 Thanks!

One last thing, how do you know that its transferring 2 bits per cycle? and how would you find an external bus speed?

Thanks yo

 

[jjyiz28]

i know it transfers 2 bits per cycle because thats what ddr memory is. dual data rate

external bus speed?? i guess you could find out by running programs, such as aida32, wcpuid, sisandrasoft, that tells you your fsb.
easier way is to check your manual, or your bios, to see what your external bus speed is running at.
or if you know what chipset you have and processor, anyone could tell you what it should be running at.