Memory speeds?

[ctmagnus]

I need <Tim "The Toolman" Taylor voice>MORE RAM!</Tim "The Toolman" Taylor voice>. However, the sites I've been looking at state PC2100, PC2700, PC3200, etc. and my manual says 533MHz DDR2. How do the PCxx00 numbers and MHz compare?

[Nurhisham Hussein]

None of those will work actually - you need PC2xxxx modules. See here for more information:

http://en.wikipedia.org/wiki/DDR_SDRAM

http://en.wikipedia.org/wiki/DDR2_SDRAM

[ctmagnus]

That doesn't really answer my question. :?

I found this (http://www.ec.kingston.com/ecom/configurator/modelsinfo.asp?SysID=22033&mfr=Toshiba&model=Tecra+M4&Sys=22033-Toshiba-Tecra+M4&distributor=0&submit1=Search), which states that I can use darn near any configuration of Kingston's reasonably-sized modules, so that's one less thing to worry about.

Anyone else up for the PCxx00 vs MHz question?

[Nurhisham Hussein]

Based on the link, are you looking specifically at laptop memory? This differs considerably from normal PC memory as newer laptops use the SODIMM 200pin bank, as opposed to the 184pin bank norm on PC motherboards. The thing I was trying to point out is that DDR and DDR2 banks are not necessarily compatible, hence why I said you can't use memory modules denoted PCxxxx, you need PC2xxxx. In any case, the links I gave provided the number-MHz conversion:

For DDR:

Chip specification

* DDR-200: DDR-SDRAM memory chips specified to run at 100 MHz
* DDR-266: DDR-SDRAM memory chips specified to run at 133 MHz
* DDR-333: DDR-SDRAM memory chips specified to run at 166 MHz
* DDR-400: DDR-SDRAM memory chips specified to run at 200 MHz

Stick/module specification

* PC-1600: DDR-SDRAM memory module specified to run at 100 MHz using DDR-200 chips, 1.600 GByte/s bandwidth per channel.
* PC-2100: DDR-SDRAM memory module specified to run at 133 MHz using DDR-266 chips, 2.133 GByte/s bandwidth per channel
* PC-2700: DDR-SDRAM memory module specified to run at 166 MHz using DDR-333 chips, 2.667 GByte/s bandwidth per channel
* PC-3200: DDR-SDRAM memory module specified to run at 200 MHz using DDR-400 chips, 3.200 GByte/s bandwidth per channel

For DDR2:

Chip specification

* DDR2-400: DDR-SDRAM memory chips specified to run at 100 MHz, I/O clock at 200 MHz
* DDR2-533: DDR-SDRAM memory chips specified to run at 133 MHz, I/O clock at 266 MHz
* DDR2-667: DDR-SDRAM memory chips specified to run at 166 MHz, I/O clock at 333 MHz
* DDR2-800: DDR-SDRAM memory chips specified to run at 200 MHz, I/O clock at 400 MHz
* DDR2-1000: DDR-SDRAM memory chips specified to run at 250 MHz, I/O clock at 500 MHz

Stick/Module specification

* PC2-3200: DDR2-SDRAM memory stick specified to run at 200 MHz using DDR2-400 chips, 3.200 GByte/s bandwidth per channel.
* PC2-4200: DDR2-SDRAM memory stick specified to run at 266 MHz using DDR2-533 chips, 4.267 GByte/s bandwidth per channel
* PC2-5400: DDR2-SDRAM memory stick specified to run at 333 MHz using DDR2-667 chips, 5.333 GByte/s bandwidth per channel
* PC2-6400: DDR2-SDRAM memory stick specified to run at 400 MHz using DDR2-800 chips, 6.400 GByte/s bandwidth per channel
* PC2-8000: DDR2-SDRAM memory stick specified to run at 500 MHz using DDR2-1000 chips, 8.000 GByte/s bandwidth per channel

For your 533Mhz DDR2, that would mean you need PC2-4200 modules/sticks (remember DDR means Double Data Rate, so 266Mhz x 2). HTH.

[Nurhisham Hussein]

I might also add that it's pretty safe to use different rated memory (in MHz) from your existing memory module - but the whole will be restricted to the slowest memory module speed unless you explicitly force the clock higher through the BIOS settings. While this works (sometimes) it does potentially cause instability.

[ctmagnus]

Based on the link, are you looking specifically at laptop memory?

:oops: Guess I should've mentioned that.

For DDR2:

Chip specification

* DDR2-533: DDR-SDRAM memory chips specified to run at 133 MHz, I/O clock at 266 MHz

Stick/Module specification

* PC2-4200: DDR2-SDRAM memory stick specified to run at 266 MHz using DDR2-533 chips, 4.267 GByte/s bandwidth per channel


For your 533Mhz DDR2, that would mean you need PC2-4200 modules/sticks (remember DDR means Double Data Rate, so 266Mhz x 2). HTH.

Thx!