Newsgroup: it.comp.hardware
Titolo: distinguere le RAM

Salve,
si possono distinguere le varie caratteristiche (velocità del bus, 
latenza e altro...) dei moduli di RAM dai codici che ci sono stampati 
sopra ? presumo di si ma  dove posso trovare informazioni in merito?
grazie 
Marco.


Se sono certificate, dovrebbe esserci un adesivo con una scritta 
molto esplicativa. Qui una breve guida:
PC66/100 SDRAM Intel Specification - Version 1.0 to 1.2: 
PCx-abc-defm (e.g. PC100-322-622R) where: 
x - Speed rating (MHz). Memory bus speed should be equal or lower 
than this. 
a - CAS latency (cycles). Lower the better (faster), but more 
expensive. 
b - RAS to CAS delay (tRCD cycles). Lower the better. 
c - Row precharge (tRP cycles). Lower the better. 
d - Read data access time (tAC ns). Lower the better. 
e - SPD chip revision. 2 corresponds to SPD 1.2. 
f - Design revision. 2 corresponds to Rev 1.2. 
m - R for registered DIMMS. 256MB and bigger modules need to be 
registered. 
PC66/100 SDRAM Extended Intel Specification - Version 1.2b+: 
PCx-abc-ddeefm (e.g. PC100-322-54122R) where: 
x - Speed rating (MHz). Memory bus speed should be equal or lower 
than this. 
a - CAS latency (cycles). Lower the better (faster), but more 
expensive. 
b - RAS to CAS delay (tRCD cycles). Lower the better. 
c - Row precharge (tRP cycles). Lower the better. 
dd - Read data access time (tAC ns). 54 corresponds to 5.4ns. Lower 
the better. 
ee - SPD chip revision. 12 corresponds to SPD 1.2. 
f - Design revision. The current is 2 corresponding to Rev 1.2. 
m - R for registered DIMMS. 256MB and bigger modules need to be 
registered. 
PC133+ H/E/VC/SDRAM IBM/VIA/Micron/NEC Specification - Version 2.0: 
PC133m-abc-dde (e.g. PC133U-222-452, PC133R-333-542) 
m - Module Type (R = Registered, U = Unbuffered). 
a - CAS latency (cycles). Lower the better (faster), but more 
expensive. 
b - RAS to CAS delay (tRCD cycles). Lower the better. 
c - Row precharge (tRP cycles). Lower the better. 
dd - Read data access time (tAC ns). 54 corresponds to 5.4ns. Lower 
the better. 
e - SPD chip revision. 2 corresponds to SPD 2.0. 
PC200+ DDR SDRAM Micron/Samsung/Hyundai Specification - Version 1.0: 
PCxm-aabx-dde (e.g. PC266R-2533-750) 
x - Speed rating (MHz). Memory bus speed should be 1/2 or lower than 
this. 
m - Module Type (R = Registered, U = Unbuffered). 
aa - CAS latency (cycles). Lower the better (faster), but more 
expensive. 
b - RAS to CAS delay (tRCD cycles). Lower the better. 
c - Row precharge (tRP cycles). Lower the better. 
dd - Read data access time (tAC ns). 54 corresponds to 5.4ns. Lower 
the better. 
e - SPD chip revision. 0 corresponds to SPD 1.0. 
RDRAM Rambus Specification - Version 1.0: 
xMB/a b c PCd (e.g. 256MB/16 ECC PC800) 
x - Module size in Mbytes on the module. 
a - Number of RDRAM devices on the module. 
b - Error correcting support (e.g. ECC) 
c - Reserved. 
d - Speed (Mega data transfers per second, Mt/s). 
Se parli delle sigle stampate sui chippini di memoria, la cosa si fa 
più complessa.
Se hanno il chip SPD, si potrebbe usare un programmino per leggere le
specifiche, una volta montate. Ne trovi a bizzeffe.
Oppure prova ad usare un motore di ricerca, od a postarle... 
qualcuno potrebbe riconoscerle.
In ogni caso, se ne sei già in possesso, fai delle prove: *nessun* 
rischio di danneggiamento hardware. Inoltre, ogni pezzo, entro certi 
limiti, è diverso dagli altri.
-- 
Bye.
       Lem
--------------- 'CLOCK is what you make of it' ---------------
Nuovi numeri primi, con Prime95: 
www.mersenne.org/freesoft.htm