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I'm looking to install some extra DDR1 RAM into a computer, but while looking online for some, I see all these extra specs, like "Assorted Models PC3200 400 MHz DDR1 Desktop RAM". Do any of those other numbers matter? I've searched online, but I can only find info about differences between DDR1, 2, and 3.

Indrek
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Nathan
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    They all matter. For instance 400Mhz is the frequency.. Check your motherboard manual for support memory configurations. – Ramhound Oct 27 '13 at 23:08

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Depends on who you ask, and on the speed of the system. This is a particularly old system, and many of the considerations that you'd have with a modern system do not play a part here.

I think the most important thing to start with is, your ram is only as fast as the slowest stick of ram you have on your system, and the speed is the fastest speed it can run at - 400mhz is the fastest DDR1 ram you can buy, so thats a good option, since DDR is backward compatible with lower frequency FSBs. tldr get the fastest ram you can, or minimally get ram with the same frequency as your fsb. You can convert the PC XXXX numbers to FSB speeds by dividing by 4 for DDR ram

With old school ddr, the MHZ rating refers to the front side bus speed the processor runs at, and I do believe that its a good idea to get ram of the same FSB speed or better - since faster ram is backwards compatible. This may be different with newer ram, but at least up to ddr2, this is true. Crucial has an great article on ram speeds which I referenced heavily in this answer. I'd note with modern ram faster may not always be the best option, but in this case, it would be I believe

I'd also note that with newer/enthusiast level ram, when you're overclocking a system, many of them also have a cl timing/latency rating listed - this is primarily useful when overclocking and tells you how many cycles the memory will delay to get you data - in this case, the lower the better. This shouldn't be an issue here - just get the fastest ram you can, assuming it isn't massively overpriced, as often happens with older ram.

You might also look at whether this is ECC ram (servers use this), registered ram (likewise) - ram can also be both, or neither. You cannot mix registered and unregistered ram, and not all motherboards support registered ram. Wikipedia has a decent writeup on registered ram here. Most desktop ram is neither ECC nor Registered. If this is a server, look up your documentation, or just get the same sort of ram you already have.

Journeyman Geek
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  • Perfect, except all RAM has a CL / #CAS / Timing, but it really is unimportant compared to most other factors. DDR and regular SDRAM were able to get #CAS 2 or lower, but with newer RAM the increased throughput is more important than the timings alone. – Austin T French Oct 27 '13 at 23:23
  • Well, the importance of CL/CAS# is debatable on modern systems as well. On something as old as this, its a non issue. And yes, while all ram has it, unless you're overclocking, you wouldn't look at it at all – Journeyman Geek Oct 27 '13 at 23:57
  • Thanks! Lots of helpful info here that should help me make my decision. I'll wait until I get the computer on tuesday to buy the RAM. – Nathan Oct 28 '13 at 00:01