Registered Server Ram, Compatibility, and what is it?

Paulisus

Reputable
Nov 1, 2015
4
0
4,510
Hi there,
So I was in the market looking for some cheap Ram for my Desktop PC, and though I had the intention of just buying another Kingston 8Gig same speed from Amazon as my other stick, for best compatibility. I came across a post of someone selling...

4x8Gb DDR3 10600r Registered Server Ram for fairly cheap. In fact extremely cheap when you compare it to the cost of an average DDR3 8Gig stick.

However I don't know the difference between "Desktop" ram and RSR.
Is this still compatible with a Desktop's motherboard..
I have a ASUS M5A78L-M motherboard that's DDR3 I believe, for reference.

And even if it is compatible is it still better to use the 1 8Gig Kingston stick for compatibility and performance issues, over say, filling my 3 free slots with 8Gig RSR's?

Thanks for your time!
Paul.
 
Solution

therealduckofdeath

Honorable
May 10, 2012
783
0
11,160
Registered RAM only works on motherboards supporting it. So don't buy it. They're memory types with built in "repeaters" to allow for more modules on a single motherboard. The repeater is needed as normal RAM would start getting read errors if you'd keep stacking more slots onto the motherboard beyond the usual 2 supported per bank. Servers often has 16 memory slots per processor.
 


Registered memory has a register (a type of buffer) on the command and address busses.

The command and address bus is sent to every single DRAM chip on the channel. On consumer motherboards, 8-bit and 16-bit DRAM chips are used for a total of either 8 or 4 DRAM chips per rank (64 bits per rank) and up to 4 ranks per channel. Thus, there are between 4 and 32 DRAM chips per active channel on consumer motherboards, each placing its own electrical load on the command and address signal for a range of 4 to 32 electrical loads.

Servers permit the use of higher density 4-bit DRAM chips as well as Error Correcting Code, or ECC. ECC is nothing more than an additional 8 bits of memory, raising the total from 64 bits per channel to 72. 16 bit DRAM chips aren't used in servers, so this is either an additional 1 8-bit chip per rank, or an additional 2 4-bit chips per rank.

Furthermore, the maximum number of ranks is raised from 4 to 16. 16 ranks, each with up to 18 electrical loads is 9 to 288 electrical loads on the command and address bus. Registers are devices on each DIMM that capture and replay the signal that they received. This reduces the electrical load on the command and address bus from one load per chip to one load per RDIMM. The signal reaches the DRAM chips one cycle later using the DIMM's own power rather than the memory controller's power. However, a penalty of one bus cycle is incurred on all operations.
 
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