bnmohan via HWKB.com wrote:
> Does PC-133 SDRAM imply unbuffered 3.3V, or does PC-133 come in both buffered
> and unbuffered; and 3.3V and 5V
>
> Mohan
>
The example registered DIMM (RDIMM) has 9 memory chips on a side, for an array width
of 72 bits. That allows for ECC protection. There are three additional chips,
including a PLL clock buffer and register chips.
The unbuffered RAM in the example above, has 8 memory chips on a side. But
it is also available in an ECC configuration, with 9 memory chips on a side.
The distinction, is there is no PLL clock buffer and register chips, so the
module can be lower profile. The acronym that Micron uses for this is UDIMM,
which may also be a JEDEC term, but the RDIMM/UDIMM thing is not that popular
in retail advertising. Mainly because it might become confused with RIMMs or
RDRAM (RAMBUS technologies).
Of the four possible combinations, these are the types of memory you can buy
Registered with ECC (72 bit wide memory interface, same pin count)
Unbuffered with no ECC (64 bit wide memory interface, same pin count)
Unbuffered with ECC (72 bit wide memory interface, same pin count)
Registered with no ECC <------ Does not exist, server owner would not use.
The RAM above, all runs at 3.3V.
Voltage versus technology, from most recent to oldest. This is just going
from memory, and I'd have to dig through my junk pile to find the FPM/EDO
and verify the pin count.
On Mon, 14 Jul 2008 17:15:37 GMT, "bnmohan via HWKB.com"
<u35859@uwe> wrote:
>Does PC-133 SDRAM imply unbuffered 3.3V, or does PC-133 come in both buffered
>and unbuffered; and 3.3V and 5V
>
>Mohan
Since unbuffered, 3.3V PC-133 memory is the most common
type, it is *usually* assumed to be that if there is no
other descrption but "PC-133", but be sure to ask (the
seller?) to be certain of whether it will suit your needs.
Thanks all!
That was a great deal of information.
There was an ad on eBay for PC-133 SDRAM, and I wanted to be sure. The
seller said 'I dont know abt that' when I queried if it was Unbuffered 3.3V.
As mentioned, it is most probably unbufferd 3.3V, but I would like to be sure.
Mohan
kony wrote:
>>Does PC-133 SDRAM imply unbuffered 3.3V, or does PC-133 come in both buffered
>>and unbuffered; and 3.3V and 5V
>>
>>Mohan
>
>Since unbuffered, 3.3V PC-133 memory is the most common
>type, it is *usually* assumed to be that if there is no
>other descrption but "PC-133", but be sure to ask (the
>seller?) to be certain of whether it will suit your needs.
Pc133 buffered or unbuffered 
Linear Mode
