DIMM vs. PC100...

[zskillz]

Thanks to all of you who responded to my earlier post about RAM, but I do have another qestion about RAM that I though should go under a different heading.
Anyway, could someone please tell me what the hell the difference is between these 2 types. I addition, are there any other types out there that I should be aware of, and if so, how do those compare?
thanks to all,
Z

[Roy]

Study the SDRAM Survey at www.bxboards.com (http://www.bxboards.com) .

[zskillz]

"When overclocking, use a setting of CL3"
do you mean that I should make sure that the board is set for CL3 (I'm gonna have a bx6II)??.. is there just a setting in the BIOS for that...
Roy do you know of a url for an absolute newbie that explains RAM and it's function, structure, etc.?
thanks a lot man,
Z

[AuraEdge]

Heres the lowdown on as much of this stuff as i know.
A DIMM is simply the format which the ram is in. A DIMM will fit DIMM slots and not SIMM slots (the old ones)
In addition to the format, Dimms either have PC66 compliance or PC100 Compliance or the new PC133. PC66 chips are set to run on systems with FSB's of 66 or below, although you can get work some on PC100 systems, they are only guarenteed to run on PC66 systems. PC100 is the same way, except with 100MHZ FSB
Ditto for PC133 at 133Mhz. RAM will be labeled like this. "SDRAM 128MB of PC100 DIMM". This is just ONE stick of RAM's label. This means this is SDRAM that is guarenteed to run up to 100Mhz FSB that fits into a DIMM slot and carries 128MB's.
There is a setting in bios to change CAS timings. They are labled either SDRAM CAS latency time, or split into 3 catagories in the newer BIOS's. One is RAS to CAS precharge time or somthing like that. I just set all three settings to 3 cuz i dunno which one does what http://www.sysopt.com/forum/smile.gif. Anyways at CAS 3 things are a TAD slower, hardly noticable tho. but at CAS 3, things overclock easier and there is less stress put on the memory when running it out of spec. for instance, my PC100 stick of RAM will work at 124 FSB at CAS 2, but will freeze on 133 FSB. When i turn it down to CAS 3, It can run at 133 FSB, even tho this is far out of spec. Hope this helps.
there is no just CAS. CAS Latency is a timing and its either at 2 or 3, of which 2 is faster, but 3 is stabler.

[This message has been edited by AuraEdge (edited 07-28-99).]

[zskillz]

thanks bro
Z

[zskillz]

I'd edit my old message, but I don't know how, so I've just gotta repost... sorry.

I just read through that article, and I guess I just don't really understand the difference still... I mean, now I'm even more confused. Is CAS 2 better than just CAS or what? I would assume so, but I think that article just compared CAS 2 and CAS 3. Separate of that, I still don't know how pc100 compares to just regular DIMM...
thanks to respondants,
Z

[Roy]

You can edit a post by clicking on the pencil and notepad above it.

CAS (Column Access Strobe) Latency (the number of clock cycles after a request for data until valid data is available) is the best indicator of SDRAM speed. CL2 at 100 can mean the chips will run at much higher speeds. At these speeds, a BIOS setting of CL3 may be required.

When overclocking, use a setting of CL3 until you reach stability at the fastest FSB speed. Then try CL2 to see if it remains stable. The actual performance difference is too small to notice. One clock cycle at 100MHz is 0.00001 second. Don't blink. http://www.sysopt.com/forum/wink.gif

[A3]

Memory is becoming an issue again as CPU and bus speeds increase. I'm researching a new MB, and this issue keeps popping up - mostly because PC100 2-2-2 DIMMS can outperform PC133 3-3-3 DIMMS in some configurations and people want 1) to know why and 2) to max out performance. Acording to Toshiba, PC133 3-3-3 offers only a 4% increase over PC100 2-2-2 with no overclocking.

Check the following sites for discussions:
www.tomshardware.com (http://www.tomshardware.com)
www.toshiba.com/taec/components/Generic/WP_memory.shtml (http://www.toshiba.com/taec/components/Generic/WP_memory.shtml)
www.pc133memory.com/information/Craig's%20Corner.html (http://www.pc133memory.com/information/Craig's%20Corner.html)