These are a collection of my notes on PC, Desktop and Server RAM.

• Memory for my TrueNAS = Unbuffered ECC RAM (UDIMM)

• General
  • DataMemorySystems.com - Frequently Asked Questions about RAM
  • Types of RAM - An Overview Guide to PC Memory | CGDirector - There are so many types of RAM available that it can be difficult to make heads or tails of all the acronyms. DDR, SDRAM, RDIMM, ECC. We explain it all.
• Identify RAM Type
  
  • ECC RAM has an extra RAM chip, so instead of 8 matching chips there will be 9 matching chips. This chip is used to store parity data.
  • Buffered/Registered RAM will always be ECC and will have an extra chip for each memory chip. These extra chips reduced the load on the motherboards RAM controller and allows for many more DIMM slots.
  • DataMemorySystems.com - Frequently Asked Questions about RAM
    • Q: How to tell ECC, Parity memory from Non-ECC, Non-Parity memory?
    • A: If your system has ECC or parity memory the chips are evenly divisible by three. How do you know which one you have? One way is to look at the part numbers on the chips of your module. If each chip has the same part number, you have ECC. If one chip is different, you have parity.
• Memory Timings
  • Guide to RAM (Memory) Latency - How important is it? | CGDirector - All those Latency specifications on RAM Kits can become confusing when buying memory. How important are they and what Latency is best?
  • What's the difference between PC2400T and PC2400 memory? - Super User
    • The suffixes refer to the JEDEC DDR4 standard. JEDEC is a sort of trade organization / standards organization.
    • PC2400T refers to DDR4 running at a 300MHz memory clock with a 14.6 CAS latency and 17-17-17 timings (CL-tRCD-tRP).
    • PC2400 is simply a non-specified variant of DDR4 with the same memory clock.
• Misc
  • Are More RAM Modules Better for Gaming? 4 x 4GB vs. 2 x 8GB | TechSpot
    • Today we're taking a look at the performance impact having four DDR4 memory modules can have on performance in a dual-channel system, opposed to just two modules.
    • TLDR: Installing four memory modules in a dual-channel system can improve performance in certain scenarios.
• Buffered and Unbuffered RAM
  • Buffered vs Unbuffered RAM - Differences & Which Do You Need? | CGDirector
    • Buffered RAM (Memory) reduces electrical load on the memory controller, making it less likely to become a bottleneck in Systems with lots of RAM Modules.
    • This article also deal with ECC RAM in-depth.
• ECC RAM
  • Linus was right. - ECC Memory Explained - YouTube | Linus Tech Tips
    
    • It’s possible to use ECC server RAM inside of your regular desktop computer at home, but is it something you SHOULD do?
    • AMD, although has not validated ECC on their consumer platforms, they have left the technology enabled allowing the choice for motherboard manufacturers as to whether they support it or not.
    • ECC adds stability at a small performance cost.
    • ECC = Error Correction Code
    • Can correct bit flips and notify the user of these errors.
    • UDIMM ECC modules (unbuffered) will work in any motherboard that supports their capacity and the DDR4 standard but the ECC chip will only be active if we choose a motherboard that explicitly supports ECC.
    • DDR5 has ECC built into the standard.
  • I LOVE Paywalls. Thanks Intel! - ECC Support on Alder Lake - YouTube | Linus Tech Tips
    
    • 12th Gen Intel (Alder Lake) supports ECC memory, but you're going to need a specific chipset to utilize it. A chipset only available on expensive workstation motherboards that lack other features you might want... So just how badly do you need Error Correction Code memory in the first place?
    • Like Intel, AMD say ECC is a workstation and server class feature that general consumers probably don't need. they only validate it on their professional products but AMD have not outright disabled the function on their consumer CPUs and chipsets. This allows theri motherboard providers to activate ECC if they choose to.
  • ECC Memory vs. DDR5 Built in Data Checking - Infographic - Competitors are calling DDR5's Built in Data Checking ECC memory - but it is not the same.  This infographic help customers understand the difference - and why they should look for Intel based workstations with ECC memory.
  • ecc - What and how to check when determining if a memory stick will be compatible with a particular server? - Server Fault - Some Questions and answers on ECC RAM.
  • What Is ECC Memory in RAM? A Basic Definition | Tom's Hardware - What’s the meaning of ECC memory? ECC memory in RAM explained.
• DDR5 and built-in ECC (On-Die ECC)
  • The in-built ECC of DDR5 is not the same as normal ECC and is for all intensive purposes just allows manufacturers to increase RAM density.
  • Is DDR5 ECC memory? | CORSAIR:EXPLORER - Is DDR5 ECC memory? We take a look to find out.
  • What is DDR5? The PC's next-gen memory, explained | PCWorld
    • Is DDR5 more future proof? Is it faster? And what about DDR5's latency? We answer those questions and more.
    • DDR5 does indeed include ECC (or error correction control) that can detect multi-bit errors and correct single-bit errors. It is, however, not what you’re expecting if your workload already requires the technology.
    • With traditional ECC, error detection and control is performed at all levels, including the data that is transferred to the CPU. With DDR5, ECC is integrated into each actual RAM chip but once it leaves the chip and begins its journey along that long narrow wire to the CPU, there is no ECC performed, meaning errors induced along the way aren’t its problem.
  • DDR5 Memory Specification Released: Setting the Stage for DDR5-6400 And Beyond | Anandtech - an in-depth look at the DDR5 spec.
  • Why DDR5 does NOT have ECC (by default) - YouTube | TechTechPotato
    • DDR5, when it was announced, had a new feature called 'On-Die ECC'. Too many of the press, and even the DRAM company marketing materials misunderstood this important technology. It is not traditional ECC, and in fact won't do much if you really need an ECC system. Here's what it really does.
    • Also explains ECC.
    • Non-ECC is cheaper to make and give betters speeds.
  • DDR5 - Questions and answers | Crucial UK
    • Q: Is Crucial DDR5 Desktop Memory classified as ECC memory because it has the on-die ECC (ODECC) feature?
    • A: No. Crucial DDR5 Desktop Memory is non-ECC memory. The ECC as it pertains to RDIMMs, LRDIMMs, ECC UDIMMs, and ECC SODIMMs is a function that requires additional DRAM at the module level so that platforms such as servers and workstations can correct for errors on individual modules (DIMMs). On-die ECC (ODECC), however, is a feature of the DDR5 component specification and should not be confused with the module-level ECC feature. Crucial DDR5 Desktop Memory is built with DDR5 components that include ODECC, however these modules do not include the additional components necessary for system level ECC.