Memory combo

im looking to buy some more ram soon since 128 doesnt cut it these days and was wondering if i could add more ram and keep the ram that i have already.can i put in any combonation of sizes?

Yes you can mix and match Ram. One thing to remember is that the Ram in your computer will run at the slowest speed out of all of the Ram installed.

If you have ram that is rated at PC3200 (400Mhz) and some that is rated at PC2100 (333Mhz) then both will drop down to the lower speeds.

While I am here and instead of making a new thread I have also seen Non-Parity, Registered and UnBuffered along with CL 2, CL 2.5 and CL 3.

Can someone give me a quick overview of these and which is best?

Be aware of a few other things as well.

  • You must have an open slot on your motherboard to actually place the new RAM stick in. This usually isn’t a problem but take a look just in case
  • There are cases where two RAM sticks will not play nice together, thankfully it is rare but has been known to happen none-the-less. Also, mixing different speeds of RAM will increase the chance of this happening so avoid it if you can.
  • Motherboards limit the total amount of system memory that can be installed. Generally speaking, the newer the model the more memory that can be installed. Most newer computers can accept at least 1GB of RAM, but double check with you motherboard manufacturer to be sure.
  • This little user friendly guide may help answe a few questions as well.

@Womblle, a simple answer. CAS effects the speed of the RAM. Technically the lower the better. BUT, unless you are a performance freak I wouldn’t worry about getting the slower CAS 3 RAM myself. Registered RAM is primarily used in servers and has error checking in it. In a desktop it is pretty much useless and I would not get it. To tell you the truth I honestly don’t think it would even work in some desktops (I’m not 100% sure on that part though).

Originally posted by Womble
While I am here and instead of making a new thread I have also seen Non-Parity, Registered and UnBuffered along with CL 2, CL 2.5 and CL 3.

Can someone give me a quick overview of these and which is best? [/B]

ECC memory - Error-Correcting Code memory, a type of memory that includes special circuitry for testing the accuracy of data as it passes in and out of memory. The terms “non-parity” and “non-ECC” are both used to describe memory that does not have any error detection or correction abilities.

DDR and SDRAM can be unbuffered or registered. EDO and FPM can be buffered or unbuffered. Buffered modules contain a buffer to help the chipset cope with the large electrical load required when the system has a lot of memory. Registered modules do not have a buffer but do contain a register that delays all information transferred to the module by one clock cycle. Buffered and registered modules are typically used only in servers and other mission-critical systems

The term latency, is best described as the time between a command being issued, and the command being carried out. The most talked about form of latency affecting the computer system, is that known as ‘CAS Latency’. CAS stands for ‘Column Access Strobe’. Its best to think of the RAM as a table of data, with information being stored in rows and columns. In order to retrieve data from RAM, the processor needs to ask for it using both a column and a row identifier. While the CAS is the signal sent to identify the column, there is of course also a ‘Row Access Strobe’ or RAS to select the correct row. When the chipset asks the RAM for data, it first activates the RAS signal to select the row, then there is a slight delay for a few clock cycles (called RAS-to-CAS delay) before the CAS signal is activated, selecting the right column, then there is another pause (CAS latency) for a few clock cycles, before the required data is returned. On modern memory sticks, terms such as CAS 2 and CAS 3 are used. Basically the number refers to how many clock cycles we have to wait between sending the CAS signal and getting the data returned.

While agreeing with all posts above…some other cautions…

  1. there is more than 1 kind of ram. Depending on your machine, and it’s age…just going to the local Best Buy or pc shop will be bad if you buy say…DDR Ram if your machine supports Dimm or Rambus…or dare I say it…“72pin Simm”…:slight_smile:

Know what type of ram you PC has before buying more.

  1. Ssseth is correct, make sure you have an open slot or two to add more ram on your main board,orhterwise, you’ll have to replace what you have with higher capacity sticks.

  2. Depending on your main board,you cannot mix and match. On the newer board today, you certainly can…and the posts above provide a good inkling to pros and cons…but all not older boards support this, some older boards in the 1ghz rang and lower require “matched pairs”.

Most important of the 3…Know what kind of ram your board takes…DDR 256 meg sticks are a steal at a good price…but useless when you get them home and open the case to find your board supports only Rambus or PC133 Dimms…:slight_smile:

One quick add in, a warning, for older boards. Like ZigZagMan said most current day boards you can mix and match as much almost as you like but with older boards you must be careful.

Some older boards are restricted, for examplem the highest RAM mod they can take is say 256, but you go and buy a 512 stick, come home all happy, put it in, and not all is so fine and dandy because its unrecognized even with latest BIOS on an old board. So always find the maxx SIMM or whatever RAM type it is any older model baord can take first… because your 512 piece in our example would nto bedefective and you would be subject to a restocking fee if returning it.

I don’t think you can mix SDRAM with DDR RAM can you?

Originally posted by $CyBeRwIz$
I don’t think you can mix SDRAM with DDR RAM can you?

Depends on the board. In some instances, yes you can, same way some older TXII Pro boards allowed to mix old style 72pin memory with new SDRAM 168 pin memory and it can read them and combine. However, you would have lower access time, usually the lower RAM present.

Just make sure you don’t use memory chips that require different voltages. This will eventually kill the stability of your motherboard.

yeh i have a 128 PC-133 which is SDRAM i think…im using a pent 3 board…

Hello Neo,

Now that you know it’s pc133, all you need to know is you have additional dimm slots. If so, we know your board atleast supports 128meg pc133’s. If you have 2 slots free, add two more 128’s and your up to 384 meg ram. My guess would be that your board supports 256meg stick also…I’d be iffy on 512’s.

Best to check your boards manual, or look it up online to see what the max stick size your board will take.

On the good side, pc133 is dirt cheap compared to faster ram types like DDR or Rambus. Even though pc133 is not nearly as fast as the other 2, you should see a major improvement upgrading from 128 meg to 256+

This box of mine runs on pc133, it has 3 dimms. 1 pc133 256meg and a pair of pc133 128’s. It was ram I cobbled from my old Duron 800 when I upgraded the mainboard and CPU.

It’s no rocket sled by todays standards…but it’s a real good workhorse…:slight_smile: