Should I get ECC Memory on Sabertooth 990FX? Is it really supported?

Vandroiy

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Jul 14, 2011
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I just got myself a new motherboard, the Asus Sabertooth 990FX. On the website, the specifications read "ECC, non-ECC, unbuffered...", but in the manual, it only says non-ECC memory can be used!

I am fed up with RAM that runs well on one day and fails spontaneously another time. ECC seems a great way out -- does anyone know what the disadvantages are? Any benchmarks, experiences? Guesses on whether the Sabertooth supports ECC RAM?

Edit: one more question: on Kingston RAM, does anyone know the difference between "Elpida C-Die", "Hynix B-Die" and a module that has no further classification? If I get the latter, might I get mixed types?
 

Vandroiy

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Why should I not use ECC memory? Is there any reason apart from the difference in price? The system is somewhere between a server and a desktop; it will probably run 24/7. I would like to install at least 16 GB of RAM at some point. From all I know, bit-flips can become an issue with that much memory already. (Which makes sense -- come on, 32 billion bits on each module, one will malfunction at some point!)

There have been posts claiming I will lose about 2% of performance using ECC; are they referring to the higher minimal CAS latency of ECC RAM, or is there some additional performance factor that doesn't show in RAM specs?

Anyways, I'm still not sure whether I can use ECC RAM. Most of what I find online seems to confirm that it is possible. Maybe an error in the manual?
 

Vandroiy

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Does the "slower" refer to CL9 or maximum available frequency? Or is there something else?

I know I won't be able to run ECC RAM on non-specified speeds, and have no intention of doing so. As far as the "true server setup" is concerned... do you mean the motherboard? I like the Sabertooth so far, and from my experience, the more expensive Asus gamer boards are quite reliable.

But yes, I do want reliability, and got an expensive PSU and a RAID 5 in that machine for the same reason. If trading CL7 for CL9 ECC is what it boils down to, so be it. I just want to know whether there will be more performance penalty than that change in latency.

To ask more clearly: Is DDR-1333 CL9 RAM faster than DDR-1333 CL9 ECC RAM? So, is the performance penalty for ECC somehow not included in timings and frequency? Or can I rely on frequency and latency determining performance?
 
ECC ram is slightly slower, but more accurate. UNregistered ecc may actually work on some boards, but normally costs more. I still recommend the gskills ripjaws 1600 for the asus board you listed. You can pay extra for cas 8 timings, but I honestly don't believe it's worth the extra cost. The 9-9-9-24 is the standard timings for most 1600 ddr3. If you want to try overclocking, then definately don't use ecc ram. I had an easy time overclocking my i3 to 3.67 with the stock Intel heatsink. I drop the ram setting a notch, then increase the cpu fsb by 20% for a safe overclock. So, 1600 ram would be manually set to 1333, and 200 fsb amd cpus would be set to 240 for a safe overclock.
 

vib3

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@Vandroiy

I am building new server and thinking about using ECC memory. ECC memory is recommended for servers so i thought buying
few KVR1333D3E9S/4G. But I also thought about buying saberbooth 990 motherboard. But its' a little bit confusing if it really supports ECC-memory. Here is info about motherboards that support KVR1333D3E9S/4G (basic 1333Mhz ECC)

http://www.ec.kingston.com/ecom/configurator_new/models.aspSystem=&Distributor=0&OriginalSysPN=&Manufacturer=&KTCPartNo=KVR1333D3E9S%2F4G&root=&LinkBack=&submit1=Click+Here

There is no saberbooth 990, so my conclusion is that it doesn't support ECC. You can ask from Asus from their website using "technical inquiry form", they want motherboard serial so I can't do it.

~Vibe
 

vib3

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Kingston ECC works fine with board, but not EDAC support for DDR3 yet.

And this board seems to have IOMMU support but it has just IOMMU GART not Vt-d. but it seems that BIOS is just missing ACPI IVRS table. Contacting soon to ASUS support to get this fixed hopefully.
 

Rakessh

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ECC is slower because it uses a bit of the memory bandwidth to |scrub| the memory. So it has to read sets of 64 bytes, checksum it and then write it back to memory, so it may also induce a tiny bit cpu overhead. A scrubbing interval of say 0.5ms should be good for 8GB of memory. Depending on memory frequency it should be completely scrubbed inside 24 hours and starting from scratch again (this process is continuous). There are resources on the net to calculate it properly for your memory modules and settings, just google it :)

Cheers