64GB 2133 1.6v kits - able to run undervolted?

[Stilez]

IHi,

I'm a heavy memory user (VMs, data crunching, etc). I'm upgrading from i7-2600K with 4x8GB 1866 RipjawsZ kit. It overclocked gorgeously on a Z68 Asus board to give me 2200 MHz @ 1.5v rock solid stable. But 32GB isn't enough, so I'm moving to 4960X + X79-Deluxe + 64GB. This gives a choice of 3 kits -

F3-1866C10Q2-64GZM - 64GB CL10, 1866 @ 1.5v.

F3-2133C10Q2-GZM and F3-2133C90Q2-GZH - 64GB CL10 and CL9, 2133 @ 1.6v.

I've read up on the 1.6-1.65v question in this and other places (I admit to being nervous/uncomfortable running IB-E memory @ 1.6v due to lack of headroom), and the issue of QVL, and also I have read that it's not so easy difficulty running 64GB as 8 DIMMs at higher speed, and the strain that o/c RAM places on the memory controller. My system is used for virtualisation and heavy crunching, so it probably won't run at max 24/7 but will be under load 24/7, needs to be stable 24/7 long term, and may not be replaced for several years.

So for this reason I feel uncomfortable running my DIMMs at more than about 1.53 - 1.56v. I can always get the 1866 kit @ 1.5v and be "safe". Perhaps it'll allow some overclocking, though a post on [H] says that 8x8GB may not achieve much beyond 1600-1866. I also have to buy from overseas so returns are expensive if unstable.

My question is, in G.Skill's experience, what kind of better outcome might I achieve by getting one of the two 2133 64GB kits and running it undervolted @1.53-1.56v, compared to the 1866 kit running at stock voltage @ 1.5v or a little over?

For example, will it be likely to allow any gain, such as better clocking, or lower latency/tighter timing?

Thanks!

[supahos]

I'm pretty sure your best bet will be Model #: F3-2133C9Q2-64GZH

You might get Gskill to confirm but It is better memory across the boards from the other 2 kits. I don't think it needs that much voltage to attain rated speed but it might need it to quite hit those timings. Every set of their good memory I've owned could either be under volted at rated speeds or overclocked without touching voltage. So I can't image those are any different, tho I can't imagine 1.6v making much difference if you have a good powersupply. I'm pretty sure this kit was designed for EXACTLY what you are building and should work fine in it.

[Stilez]

You might get Gskill to confirm but It is better memory across the boards from the other 2 kits. I don't think it needs that much voltage to attain rated speed but it might need it to quite hit those timings. Every set of their good memory I've owned could either be under volted at rated speeds or overclocked without touching voltage. So I can't image those are any different, tho I can't imagine 1.6v making much difference if you have a good powersupply. I'm pretty sure this kit was designed for EXACTLY what you are building and should work fine in it.

The power supply is pretty good - it's a few years old Antec CP-850 on a par with their Signature for stability/ripple suppression (review), and I'm not using gaming video cards or SLI power loads.

What's the best way to get the extra input on this thread, that you're suggesting?

[supahos]

At some point in the next 3 or so hours Gskill tech or Gskill support will log on and answer most of the questions on here. Will get better advice from them on exactly what your asking, I acutally bet they've put that memory kit in that motherboard with that processor at some point and could likely tell you the results. However anything different from spec they Won't guarantee, they are a business so making a guarantee something will work outside of the norm for their product would be silly, best you can hope for is "it worked like this for us."

I think that kit is your best bet, and it will do what it claims at 1.6v I can't imagine that would hurt anything, but that decision is between you and your IMC :P

[Stilez]

I acutally bet they've put that memory kit in that motherboard with that processor at some point

I suspect so, too

best you can hope for is "it worked like this for us." I think that kit is your best bet, and it will do what it claims at 1.6v I can't imagine that would hurt anything, but that decision is between you and your IMC :P

Indeed. I'm after info about how the 64GB kits perform if SLIGHTLY undervolted, if one wanted to stay a bit closer to "official" Intel voltage spec, and whether the kits will work at 2133+ on slight undervolting, or (if not), whether they would work at 1866-2133 on slight undervolting but with lower latency or tighter timing than usual.

Basically there's no info I can find on running the 2133 8x8GB kits (all "officially" rated at 1.6v) at say 1.53-1.56v, and that's what I'm hoping for.

[GSKILL TECH]

The higher frequency RAM uses better chips, so you can run them at a lower voltage and frequency to achieve better timings. The DDR3-1866 kit is CL10, with the DDR3-2133 CL10 kit you may be able to achieve CL9, and the CL9 kit you may be able to achieve CL8 @ DDR3-1866. It is all depending on the amount of voltage supplied. With that motherboard and CPU, you should expect some outstanding results and amazing performance.

Thank you
GSKILL TECH

[Stilez]

The higher frequency RAM uses better chips, so you can run them at a lower voltage and frequency to achieve better timings. The DDR3-1866 kit is CL10, with the DDR3-2133 CL10 kit you may be able to achieve CL9, and the CL9 kit you may be able to achieve CL8 @ DDR3-1866. It is all depending on the amount of voltage supplied. With that motherboard and CPU, you should expect some outstanding results and amazing performance.

Thank you
GSKILL TECH

Thank you! Just to confirm, the two 8x8GB 2133 1.6v kits will work at ~ 1.5 - 1.55v if I drop some MHz? In other words

1. The two "F3-2133" 8x8GB kits, though designed to run as 2133 1.6v, will indeed run stable if undervolted at 1.5 - 1.55v?
2. The main effect of running them at 1.5 - 1.55v is that (depending on the individual kit) they may not be able to run at 2133. But they will run, just perhaps a bit slower, say >1866?
3. Therefore, if given ~1.5 - 1.55v, the 2133 8x8GB 1.6v kits would still probably be as good or better performers than the 1866 1.5v 8x8GB kit, because they are better chips? (ie they won't have to drop to 1600 or 1333 to run at 1.55v!).

If that's correct understanding, and works, I will be very happy!

[GSKILL TECH]

1. Yes, you may need to raise timings to maintain DDR3-2133, or you can lower MHz to maintain/lower timings.

2. Yes, instead of raising timings to be stable at a lower voltage, you can also lower MHz and timings. You can use a memory benchmark test to see which method is better performing.

3. They will surely perform better and be capable of better specifications than the DDR3-1866 kit. They should cost more because they use better chips.

Sounds like you have perfect understanding!

Thank you
GSKILL TECH

[Stilez]

Sounds like you have perfect understanding!

Sounds like I have a large credit card bill coming soon

Thank you!

PS - I have a website suggestion. Perhaps some other people would like to run close to Intel 1.5v +/- 5%. It's a common question even in 2013 and will always get asked as long as Intel publish "conservative" or limited CPU specs. Perhaps in the G.Skill website, for modules running above the Intel "stock" voltage (1.5v, or 1.35v in future) give also their MHz at Intel voltage (1.5v) as well as at 1.6/1.65v? Same way that it lists their SPD as well as XMP spec (even though most people will use XMP). So the website will show what to expect for SPD and also XMP, and what to expect if you undervolt at 1.5v as well as 1.6/1.65v. Maybe that's an idea for the website?

[supahos]

That sounded like it would be a good idea until I actually thought about it, Each stick is slightly different, they would have to physically test each kit to see exactly what it is capable of at 1.5v in order to list it, this would make the ram much more expensive across the board just to cater to a tiny portion of the market, as Gskill Tech said the faster memory is better memory, so even at lower voltage it should perform better, it'll just be up to the end user to find out exactly what they can do, such is the case for all computer parts the end user runs out of normal spec.

[Stilez]

That sounded like it would be a good idea until I actually thought about it, Each stick is slightly different, they would have to physically test each kit to see exactly what it is capable of at 1.5v in order to list it

Not so. An indication is enough - take 40 of the kit or module, run them at 1.5v, and see what speed they run up to. Then give a "no guarantee" indication on a separate page for those looking:

Eg, a page for undervolting sample results, which lists for each kit (a) the minimum speed all 40 kits reached at 1.5v, and (b) the speed range reached by the middle 80% of kits.

It's enough for those looking for "some idea of expectation" and it's easy enough to say that G.Skill do not test every kit at 1.5v unless designed for that voltage, so these are indicative samples findings only. A bit like how Asus overclocking guides will say that 10% of a given CPU reach 4.6GHz, 40% reach 4.5GHZ and 2% reach 5GHZ+. Doesn't need to be more than a small sample, to be very helpful to a user.

[supahos]

Well that number is easy, it'll be the speed of the top end 1.5v sticks with slightly better timings I get what you're saying but there are some big differences in what they can do depending on the system they are in maybe even moreso than between kits.

IE: I have 2 mixed sets of 2x4gb 1600 mhz in my computer, one I built for my parents is just 1 2x4 set and I get better timings and speed out of my computer with any of the 3 sets mixed in, her computer just flat doesn't like 1866 speed at any timing, and won't run with a CR of 1 at any timing but stock XMP, On my computer with same memory I can tighten everything up, or speed it up all on stock voltage with any of the sets mix matched. We have the same nearly everything but I gave her an I3 I have I5 3350p

[GSKILL TECH]

supahos nailed it.

Officially, it's just not something we can do, it's much more confusing to mention it MAY** do this this that..

It is why we have a forum board and why I'm here.. for RAM tweaking, it comes down to the user knowing how to tweak the RAM, and learning the necessary info. There is no other way around it. A person that doesn't care, or doesn't want to learn the basics about tweaking RAM should not be buying extreme RAM unless they purchase fully compatible hardware to attempt XMP.

SPD values are the Intel, limited, conservative values. So for any DDR3 memory kit, if you want standard 1.50V values, you can always count on SPD DDR3-1333 CL9 and DDR3-1600 CL11 1.50V

If you purchase high end RAM, anything in between is for you to find out.

Generally speaking, for every 266MHz, you can reduce each timing number by 1.

So DDR3-2400 10-12-12-31 can be DDR3-2133 9-11-11-31 and DDR3-1866 8-10-10-31.. so forth..

These are just guestimate values you can start from, then test and work your way down.

Also, for example, if you have Trident X DDR3-2400, you can use the same timings as the DDR3-2133, DDR3-1866, and DDR3-1600 kits (generally). Since technically better chips are used, you may be capable of even lower timings, but again, that is up to the user to test and find out.

Thank you
GSKILL TECH

[Stilez]

Thanks for the detailed info. I now have a couple of last concrete questions to wrap up which RAM kit to get (it's going to be a G.Skill, question is which!).

My tasks: Mainly virtualisation (4-6 VMs) and data/number crunching (eg 3GB excel spreadsheets). 1% or 2% extra performance may not matter but added performance won't be wasted. 24/7 stability is essential. I'm maxxing out 32GB RipjawsZ 1866 o/c @ 2200 on Asus Z68, so LGA2011 and 64GB is the next step.
My kit: 4960X; Asus X79 Deluxe; H100i or Kraken X60 cooler (probably X60 due to performance in "quiet" mode?); Antec CP-850 PSU (high quality/stability); and one of the four 2133/2400 64GB G.Skill kits below.

Q.1: Raja@Asus has just now posted a thread on DDR3 considerations for LGA2011/X79 Deluxe/Ivy Bridge E. He doesn't discuss 8 x DIMM outcomes so much, but makes it sound like 8 x DIMM is hard to get working at high speeds, on IB-E, especially if the CPU itself will be overclocked. On the other hand G.Skill sells 8 DIMM kits specifically stated to run at 2133 or 2400 MHz on LGA2011/IB-E, although at elevated voltage (1.6 - 1.65v), which suggests that these speeds are usually achievable and stable (with good care and reasonable cooling). I'm not sure how to reconcile these two statements. Is it usually the case that with good RAM and cooling, most IB-E will handle 8 DIMM G.Skill kits at their stated speeds of 2133~2400, or is it correct that some significant percentage of IB-E chips will not be able to run 8 x DIMM above ~1866 however good the RAM is?

Q.2: to run 8 x DIMM at Intel spec voltage, I would probably buy overspecified (higher quality) 8 DIMM 1.6 - 1.65v kit as suggested earlier in this thread, but run the kit undervolted at 1.5 - 1.55v with slower clock or modified timings. Then see how high performance was possible without raising voltage above ~1.55v. I'd lose frequency, but gain on cooling and stability, and perhaps also achieve lower CL7-9 latencies @1866~2133 @ 1.55v even if I can't get high frequency. I find it hard to guess what would happen. I have a choice of 4 affordable kits:

F3-2133C10Q2-64GZM (1.6v 2133 C10)
F3-2133C9Q2-64GZH (1.6v 2133 C9)
F3-2400C11Q2-64GZM (1.65v 2400 C11)
F3-19200CL10Q2-64GBZHD (1.65v 2400 C10)

I know every kit is individual, and there isn't a single "right" answer, but if I were choosing a kit, I would set a "hard limit" of ~ 1.55v max, and whichever kit would give best stable performance/real world results at that voltage. Presumably any kit might excel by running at a higher MHz compared to other kits @ 1.5v, or by running at not "the top" MHz but lower latency. I know it's very variable kit by kit. But are there any generalisations you can make about these 4 kits, and how they might compare, to help me choose? Say I ran all 4 kits o/c as much as possible with an "across the board" voltage limit of 1.55v, what sort of outcomes might I get? Any impressions?

Thank you

[supahos]

F3-19200CL10Q2-64GBZHD would be the best kit that exists on that list, followed by F3-2133C9Q2-64GZH, seems to be a $40 difference in price on newegg, usually that would be enough to make me pick the cheaper one, but hell if you're spending that much on memory, and are already using up 32GB of memory, I would likely opt for the best available. the H/M/L that is the next to last letter in the name stands for High or Mid, or Low (Black, Blue, Red ripjaws in that order) which refers to its OC potential. If you are actually hitting the limit on 32GB then running 64 gb even if its slower will likely be faster for you. If you buy an 8 stick kit, they have all run together at the rated speed in a machine at Gskill, Now how they are handled after they leave Gskill's hands can affect their workability when you get them to yourself.

They should all work together, and your best bet is the black ripjaws (best chips inside) to get them to do what you're asking them to do. Whatever it is you're asking this computer to do, by god it ought to do it once you put all of that into it! Hell you could install windows on your memory, and then use it to do other things lol. It "may" require voltage tweaks in other places than Vdram in order to make everything stable as you want it, but this site will be here if you need help with that as well.