• When you reset the CMOS, the POST-ing up to RAM initialization takes a little longer because there is more probing and initialization going on (e.g. CPU detection).
• This extra time gives the CPUs a few hundred milliseconds longer to initialize the RAM

gordan79
Just out of interest - did you have any luck with getting it to post with 6x16 on a single socket? Also, do you have access to quad-ranked RAM you could try? The thing that bothers me is that a DR DIMM is electrically and electronically identical to 2xSR DIMMs on a single bank. Yet the former works and the latter does not. If the problem is RAM "density", rank count is used to reduce that, so bumping up the rank count to quad might help, even though it would necessitate down clocking the RAM.
 
Also, with 6x16, does it "just POST" on a cold boot or does it require many cycles to get it to come up?

sam nelson
yes u are right but can at times be a little bit of a pain . its kind of like 4way sli with 780 ti's and doing 4way with 780's the 780ti's will 4way with all the new drivers and game ready stuff np. you can do 4way with 780's but u have to go back to a holder set of driver . and pull some titan inf fill out of one and put thim in the fill . it work very well found it on the net the only problem is if u play a game online with them that updata's every time u play and are using win 8.1 it redoes your drivers to all new and drops u back to 3way all that is supported for them but they will runn 4way with the right software
 

tived
Hi,
I had no luck over locking with 12x 8gb ecc 1333 Kingston on my X5650's
However others have been able to do so with Crucial ram but they have also had faster processors X5680 which some seem to think will make a difference.

You can try with your 12x 8gb non-ecc they should work but if they will over lock is the luck of the draw 😄

Henrik

Ps: English is my second language too ☺️

gordan79
4.5GHz? Dream on. If you get to 4GHz stably (including TurboBoost) count yourself very lucky. Don't believe the fisherman's tales.
 
And did I read that right that your Xeons are ES Xeons? Abandon all hope of them picking up all your memory banks at more than 1333MHz RAM speed. In reality, that means you need to achieve either 166 bclk (with 1066 multiplier, relatively easily achieved with 48GB of RAM) or 222 bclk (not going to happen, don't even bother trying). In practice this means you'll be running with the 800 multiplier and actual memory clock speed substantially below 1333MHz.
 
Nobody has ever managed to get ES Xeons to post with 12x8GB. Even early retail Xeons struggle to post with 12x8. 6x8GB works fine, however, as long as you don't go above 1333MHz on memory speed.
 
Even with later retails Xeons, OC-ing is problematic. I am running 2x X5650 with 12x8GB with the methods mentioned above, and I was regularly getting correctable memory errors on CPU#1,Channel#2,DIMM#0 (i.e. first DIMM of the top channel on the second CPU). The error currently follows the slot rather than the DIMM (haven't tried swapping CPUs, the CPU in the second socket always seems a little more problematic with POST-ing with 6x8GB than the CPU in the 1st socket). This is also the memory bank that intermittently goes missing and doesn't get detected during POST on some boots when OC-ing. I have just dialed everything back to 133bclk (was running 166 bclk) to see if the error goes away.
 
Unfortunately, troubleshooting this is quite difficult because getting the whole thing to POST with 96GB is difficult enough. For example, if I run:
bclk: 166
RAM: 1333 (1666 actual)
MCH strap: 1600
it generally posts (sometimes with 80GB showing, sometimes with all 96GB showing)
If I reduce the RAM to 1066 (1333 actual with 166 bclk), it doesn't POST at all. It gets stuck in the error state withing a couple of POST attempts. So there is another interaction with something else other than pure memory clock speed going on that gets out of whack when you reduce the RAM speed. I suspect the uncore speed plays a part, but this will take some more experimentation to figure out.
 
I have also established a few other useful things:
1) vDIMM makes no difference - just set it to whatever your DIMMs are rated at (usually 1.35V). There is nothing to be gained from boosting this up to 1.65V that the "auto" setting defaults to when OC-ing, unless you are actually manging to run your DIMMs at faster speed than they are rated for (which you most likely won't succeed with 6 let alone 12 8GB DIMMs, especially since you can get 1800MHz DIMMs)
2) In fact - most voltages make no difference to POST-ing with 96GB without OC-ing. I currently have reliable posting with all my voltages hard-set to defaults:
vCore: 1.0875
VTT: 1.20
vDIMM: 1.35
IOH: 1.100
 
with all the multipliers hard-set to default:
bclk: 133
CPU multiplier: x20
QPI: 6.4GT
RAM: 1333
MCH strap: 1333
Uncore: x20
 
With the DIMMs I listed above (Crucial DDR3-1600 ECC RDIMM x4 DR 1.35V) this POSTs within 10 seconds every time. I'm going to leave it running for a week and give it a proper workout to make sure the correctable RAM error has gone away. If it has, I'll start tuning my way back up to 166 bclk.
 
So to summarize:
1) You are not very likely to achieve 100% stability beyond 4GHz including turbo boost. With your X5675s that means 166 bclk + TB. I very much doubt you will achieve this with ES Xeons.
Note: I define "stable" as no errors during OCCT + some of my extra proprietary stability testing based on md5sum and sha512sum computations) for about a week. 24 hours each of OCCT small and large standard and linpack tests, 4 days in total, plus 24 hours of sha512sum on a file small enough to fit into CPU caches for CPU core testing plus 24 hours of md5sum on large randomly generated files big enough to fill up the whole RAM to properly exercise the memory controllers.
2) You are very unlikely to get 96GB to POST with ES Xeons.
3) Even with using 48GB of RAM with ES Xeons expect that some of your RAM won't get detected at over 1333MHz RAM speed. Remember - X56xx Xeons were only ever designed and rated for 1333MHz RAM speed in the first place.

gordan79
I don't think it'll make much difference. 6x8 dual-rank will be virtually identical electrically and electronically as 12x4 single-rank DIMMs. Having said that, I also use 6x8GB single-rank (12x8 SR won't work) with no issues. Just make sure you keep your RAM at <= 1333MHz actual speed and it should work fine. My advice would be to aim for 166bclk with 1066 memory speed set in the BIOS which will give you 1333 actual RAM speed, and 166 bclk with boost enabled should get you to around 4GHz if your CPUs can actually handle it (which isn't that likely with ES chips - if it's unstable, disable TB). Don't push vCore past 1.30V or VTT past 1.35V, regardless of how good your cooling is as there have been reports of CPU damage.