Hi Guys,
 
Yesterday I got 128 GB of of M393B2G70BH0-YK0 RAM from Samsung (8 sticks, rated @1600 MHz, 1.35v, ECC) - which is 30nm (same as famous HCH9, which is used by the most "overclocker" brands of RAM).  I wholeheartedly recommend this RAM for Xeon E5 users.
 
In short, this RAM is >sick< - I am currently running it @2133 MHz, 1.5v CL11 stable, and I did not even bother with tweaking (just increased voltage from 1.35v to 1.5v and kept everything else @stock settings) - I am sure it can run @2133 MHz at much tighter timings, which is something I will play with in the coming days.
 
The best part - this RAM is not just rare ECC RAM which both low-voltage and rated @1600 MHz and overclocks like a beast, it is also cheap, you can buy one 16 GB stick for $173! 

All in all, if you need large amounts of RAM but also need it faster than what official Xeon E5 specs allow for... go with Sammy's of M393B2G70BH0-YK0, it won't disappoint.

I actually bought mine in Germany (where I am right now) - and even there it was cheap.
 
For U.S., just Google for it, Google Shopping lists several retailers having this RAM (I have no experience with any of them so I cannot recommend either).   Unfortunately, NewEgg does not have this RAM at the moment.

geort45

$173 for 16GB! Holy crap!

It's ECC-Registered memory for servers... It's not your ordinary RAM.

I wrongly assumed he had an SR-X, he just said he has E5's. Humm...

I thought ECC RAM was supposed to be more expensive, and the more "dense" DIMMS are usually the most expensive, the sweet spot now is at 4GB maybe (GB per dollar), I wouldn't have thought a giant 16GB dimm would be that cheap.
 
Anyway, it'd be fantastic if someone confirmed they work in a SR-2 :). I also wonder if there is a 8GB version, I guess the chances for compatibility would be higher.
 
Only downside is that I'd have to sell my current memory as it ain't ECC haha...

@geort45,
 
Yep, 4 GB DIMMs are the "sweet spot" today as they are produced in the highest quantities - but this will change soon once memory manufacturers move to 20nm.  Samsung claims they will be able to keep the same price for double the RAM.
 
Interesting thing is, Samsung also has a 1866 MHz version (!) of this RAM, which has the same number but a different suffix, not YK0 but MA, so for this 16 GB stick it is M393B2G70BH0-YMA.  But this one is >very< expensive (as in $1K expensive), probably due to very low quantities as 1866 MHz is still not officially supported by any server platform.   1866 MHz stick is probably just validated YK0 running on 1.5v/1866 MHz instead of 1.35v/1600 MHz.

And of course there is a 8 GB version (1600 MHz, 1.35v, ECC) - here:
 
http://www.superbiiz.com/detail.php?p=D3-16GR8GS&c=fr&pid=515466e9134a286eb27103a0623e9e3fb5998ef74876ff63fdaf8cc24f31d4ed
 
$70.99 a pop...    
 
@forgotton - -CH9 suffix is not low-voltage, that one runs @1.5v and 1333 MHz, so it could use lower-binned chips.
  
Here is the 16 GB, 1600 MHz, 1.35v (-YK0 suffix):
 
http://www.superbiiz.com/detail.php?p=D316GR16GS&c=fr&pid=515466e9134a286eb27103a0623e9e3fb5998ef74876ff63fdaf8cc24f31d4ed
 
Those 1.35v/1600 MHz ones are probably the highest-binned modules (save the 1866 MHz $1K ones that are outrageously expensive) that come from a real RAM module manufacturer (such as Samsung).  Typical "overclocker" RAM vendors such as G.Skill & Co are buying those chips in huge quantities and additionally test them at higher frequencies and package them in a nice colorful package (and charge a good fee for that service :) ) - However, experience with 30nm Samsung modules (e.g. HCH9) has shown that they are almost universally cable to run at frequencies much higher than the official specs - and in many cases all the way up to 2666 MHz.
 
This RAM is using the same 30nm Samsung chips and the fact that it runs @1.35v at 1600 MHz is a good sign that it has a potential to be pushed up much higher.

Hmm weird thing is, I got mine for 142 EUR (+19% VAT) in Germany, and this price (169 EUR) is pretty much in line with the typical USA<->Germany  price "parity" (take a price in US$, change $ to EUR and it is pretty much like it) - it is from a Samsung distributor, and the RAM came in Samsung box etc...  so I am quite sure this should be the right price and not some kind of a discount...
 
There are people on ebay selling this RAM for ~$200.

Xeon E5 CPUs support 1066/1333/1600 MHz memory speeds officially.  Unofficially you can go all the way up to 2666 MHz, depending on how good your IMC is and, of course, memory. Xeon E5 supports 16 GB and 32 GB DIMMs (buffered, ECC) but also motherboard's QPI and MRC code must support it (as it is in charge of training) - so before buying those super-expensive 32 GB DIMMS one should definitely check with EVGA if they work with SR-X.
 
Of course, if you are using full 12 DIMM slots per CPU (not on SR-X, but some Supermicro/Tyan boards support this configuration) it would probably be very dangerous to push IMC well above 1333 MHz unless you have super-quality RAM that can pull off >1600 MHz on 1.35v.  Otherwise, with over-volted RAM, the load on IMC would be extremely high.
 
Even 1.65v VDIMM is quite outside of the Intel's recommended range (which, according to Intel, should not go above 1.575v - http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/xeon-e5-1600-2600-vol-1-datasheet.pdf)
 
I run my Samsung RAM @2133 MHz, 1.5v @CL11 but I had to raise Vsa to 1.185v to be 24h/7 stable under high memory load, which is approaching maximum recommended Vsa of 1.264v.
 

M393B2G70BH0-YK0 HIHI
 
I have take 12 piece at 160$ each :D
 
Very thanks for all info psyq321.
I have imagine this OC capabilitise. You prouve it.
 
''depending on how good your IMC''
Its the problem :)
 
I just HOPE the NUMA corecly worck with 12 dim . :(

http://www.techpowerup.com/167486/Century-Japan-Sells-quot-Value-quot-16-GB-DDR3-1600-RDIMM.html
 
So a no problem with 16 GB RAM modules........
 

''NUMA should work just nice with "asymmetric"  memory configurations such as SR-X and the memory size available at each NUMA node can be programatically obtained from an application.''
 
In theorie, Yes. But I remenber some problem with SR2 and asymmetric quantity module/CPU.
all cumulated ram detected, but can be use the 3 extra modules.
 
192GB already tested, but corectly worck in real app ?
OC possiblility with IMC 8dim ... ?
 

Did you get them for a SR-2 or SR-X? Thx :)