Why is non-ECC DDR3 3x as expensive as ECC

[oboontoo]

I want to put 12Gb ram into a sx58 motherboard (only have 4 slots) but I can't justify spending 1400+ USD for it.

What I don't understand is why some ECC memory is so much cheaper.
These are some Kingston memory I've seen.

NON-ECC:
12GB 1066MHz DDR3 Non-ECC CL7 DIMM (Kit of 3)
Standard 512M X 64 Non-ECC 1066MHz 240-pin Unbuffered DIMM (DDR3, 1.5V, CL7, FBGA, Gold)
Price: $1,425
Link

ECC:
12GB 1066MHz DDR3 ECC Reg w/Par CL7 DIMM (Kit of 3) QR, x8 w/Therm Sen
Standard 512M X 72 ECC 1066MHz 240-pin Registered DIMM (DDR3, 1.5V, CL7, FBGA, Gold)
Price: $399
Link

Is the >3x price difference due to supply and demand or something else? Surely it's not >3x cheaper to manufacture the ECC memory above? Maybe the ECC mean you can get a higher yield as the unit will be able to handle internal errors (I don't know much about memory so I might just have said something stupid )?

Cheers

Martin

 

[TheInfernal]

I'm pretty sure if you look around you will find cheaper prices for both ECC and non-ECC 4GB DIMMs.
Also 4GB DIMMs are much more expensive and slower than the 2GBs. If I were you, I'd buy four 2GB DIMMs for a total of 8GB.

 

[Emulex]

Because nobody in server land wants unbuffered dimms. pretty much every server uses the ECC (duh) and 3x2gb or 6x2gb (one or two nehalem) is standard shipping fare.

Keep in mind unbuffered dimm is limited to 24GB and not nearly as stable as using a buffered dimm. Which is why if you want to fill all 18 dimm slots on a server motherboard you will only be using rdimm (registered buffered ecc).

so yeah probably all these servers folks are buying are creating a large market pool.

You pay dearly for not having NUMA balanced ram on dual E5500/X5500 systems. The sweet spot for running at full bandwidth is 12 dimms on a dual socket system. 12 x 2gb or 12 x 4gb. (ability to keep the bust at 1333mhz) The cost of 8GB gets stupid expensive. However you do have that option to exercise the expansion to 18 dimms if you need more ram.

 

[faxon]

because the demand for non ECC ram in those capacities is probably higher than what they can supply, so they are eating up the profits to fund larger scale production of such modules down the road

 

[Blain]

Originally posted by: oboontoo
I want to put 12Gb ram into a sx58 motherboard (only have 4 slots) but I can't justify spending 1400+ USD for it.

What I don't understand is why some ECC memory is so much cheaper.
These are some Kingston memory I've seen.

NON-ECC:
12GB 1066MHz DDR3 Non-ECC CL7 DIMM (Kit of 3)
Standard 512M X 64 Non-ECC 1066MHz 240-pin Unbuffered DIMM (DDR3, 1.5V, CL7, FBGA, Gold)
Price: $1,425
Link

ECC:
12GB 1066MHz DDR3 ECC Reg w/Par CL7 DIMM (Kit of 3) QR, x8 w/Therm Sen
Standard 512M X 72 ECC 1066MHz 240-pin Registered DIMM (DDR3, 1.5V, CL7, FBGA, Gold)
Price: $399
Link

(I don't know much about memory so I might just have said something stupid )?

Well Martin, it appears that you're correct... :laugh:
The memory in your first link is normal unbuffered non-ECC memory that we all use and enjoy around here.
The memory in your second link is a whole different animal. That memory is ECC "Registered", which means it's designed for server MBs, not regular desktop models.

Classic "Apples & Oranges" :roll:

BTW, An X58 chipset MB supports non-ECC and ECC (when coupled with the proper CPU), memory.
Stick with non-ECC unbuffered memory and you'll be fine.
1.5v DIMMs preferably. :thumbsup:

 

[tcsenter]

The registered modules are quad rank using 128Mx8 DRAM components, which are older technology. The unbuffered modules are using newer 256Mx8 DRAM components, which are more expensive. Still, the quad rank modules are a LOT more complex to design/make and use more than twice as many chips, plus a PLL and buffer chip. Supply must be pretty high relative to demand compared with unbuffered modules, at present time.

 

[Emulex]

dual rank is optimal for interleaving at maximum mhz (1333).


quad rank can impose some performance penalty with some intel chipsets. plus its more expensive.

stick to dual rank 4gb sticks for best bank for buck right now.