Help understanding Dell's memory descriptions

Looking over it again my guess would be that "optimized" means that it's using all 3 memory channels? But then why are the first two different? So does "optimized" mean using all 3 memory channels and 1066+ speed? But then on their listing it also shows:

How are the 72GB and 144GB "optimized" then?

Yeah, I just couldn't figure out what Dell was trying to mean by 'optimized" and "Adv ECC".

Thanks for the confirmation. Maybe they just put "Adv ECC" there for fun.

From a Dell white paper on the subject:

DDR3 Memory
There are two types of DDR3 memory supported by these systems: UDIMM and RDIMM. UDIMMs are unbuffered DIMMs, while RDIMMs are registered DIMMs. The registry allows RDIMMs to potentially run at higher frequencies and support more DIMMs within a memory channel.

NOTE: Dell systems only support UDIMMs with ECC capabilities; UDIMMs purchased for consumer systems will typically not work in the servers. Generally, RDIMMs should be purchased by customers who need large amounts of memory (up to 8 GB DIMMs), a broader future memory expansion roadmap (due to the ability to achieve three DIMMs per channel), and the latest RAS features (address parity). UDIMMs should be purchased by customers who need a limited amount of memory and are looking for power and cost savings. RDIMMs use about 1 W of power more per DIMM than the comparable UDIMMs due to the register feature. However, the register feature will allow for performance improvements when the memory is being highly utilized.

Memory Population
Each CPU has three integrated MCHs that have their own memory channel. Memory can be accessed across the CPUs, or the system can be configured in non-uniform memory architecture (NUMA). This can be configured via a BIOS configuration setting. Figure 1 shows the CPU and memory layout on the R710 model that supports up to 3 DIMMs per channel

Memory Optimized Mode
In this mode, the MCHs run independently of each other; for example, one can be idle, one can be performing a write operation, and the other can be preparing for a read operation. Memory may be installed in one, two, or three channels. To fully realize the performance benefit of the memory optimized mode, all three channels per CPU should be populated. This implies that some ‘atypical’ memory configurations, such as 3GB, 6GB, or 12GB, will yield the best performance. This is the recommended mode unless specific RAS features are needed.

Advanced ECC Mode
This mode uses two MCHs and “ties” them together to emulate a 128-bit data bus DIMM. This is primarily used to achieve a Single Device Data Correction (SDDC) for DIMMs based on x8 DRAM technology. SDDC is supported with x4 based DIMMs in every memory mode. One MCH is completely un-utilized, and any memory installed in this channel will generate a warning message during POST.



So there is your difference.....Optimized takes full advantage of the three memory channels while "Advanced ECC" ties two together and leaves on not used, doing so for better checking.