Re: PC's RAM memory explanation

[Scott Klement <pctech@xxxxxxxxxxxxxxxx>]

KVR133X64C2 stands for "Kingston ValueRAM 133mhz CL2 SDRAM at 32Mx64 
bit."   It's a Kingston part number -- not a standard code used 
throughout the industry. They can make up any codes they want, as long 
as THEY know that they mean.

Kingston happens to use meaningful names in their part numbers.  i.e. 
KVR = Kingston ValueRAM.  133 = PC133 (133 mhz BUS clock).  But even 
though they use meaningful names, that doesn't necessarily mean that the 
codes are standardized codes!

x64 means it's a 64-bit data path. The BUS in a Pentium architecture has 
64 data bits -- it always has since the original Pentium was introduced 
in 1993.  Nothing new.  It basically means that there are 64 wires 
connecting the CPU and the memory.  (Actually, there's more than that... 
but there are 64 used for sending data back and forth, the others aren't 
for data, but are for other purposes...)

If, somehow, you managed to install 32-bit memory (this was an option in 
the original Pentium days, but I haven't seen that capability in many 
years) you would have to always install 2 memory modules at a time. 
Why? Because each module has only 32 wires, and you need 64, so you'd 
have to install two of them.  This was common in the early days of the 
Pentium, because motherboards were often designed to support the same 
SIMM modules we had in the 486 computers -- which were only 32-bit, so 
we had to install them in pairs.

But, anyway... assuming you're only working with Kingston ValueRAM and 
you want to know details about Kingston's part numbers for ValueRAM, you 
can find details here:
http://www.valueram.com/datasheets/


Antonio Fernandez-Vicenti wrote:
> I've been googling to clarify some doubts, but the only thing I find are 
> lots of commercial stores that sell all types of memories.
>
> I understand that if I'm talking about KVR333 or KVR400, it has to do 
> with internal speed. Hope I'm right at this.
>
> Next, labels show X64. Does that mean it's only for PC's running 64 bits 
> apps? Else, what does it mean?
>
> Next, labels show C2 (e.g. an old one KVR133X64C2/256... ... old one and 
> X64?), or C25, or C3A
> Seems C3A are 1GB, whereas C25 are 512MB, but have some C25/256...
>
> 1- Can anybody give me some link to where all these codes are clearly 
> explained?
> 2- Can I mix KVR400 and KVR333 on same PC? If yes, am I wasting 400's 
> speed in the whole lot (would all run at 333?), or is the difference 
> negligible or even better since I'm adding additional (333) memory to 
> the 400 dimm?
>
> Thanks,