F4-3333C16Q-16GRRD can't quite get 100% stable

[porina]

I have the F4-3333C16Q-16GRRD 4x4GB kit on an Asus Maximus VIII Hero now with current bios. I picked this ram as it was on the QVL of the mobo. It appears to work fine at 3333 at first looks, but under sustained computational load, I get a detected errors within the timescale of days. Application is quite memory bandwidth sensitive, showing tens of % improvement compared to running at standard 2133.

In the bios, I've tried various things. I have XMP on and let it pick timings and voltages. I note although ram voltage is set to a nominal 1.35, it reports a measured 1.344. Is it worth tweaking it up a notch to get measured closer to 1.35? Other bios options I've tried to pick what I believe are safe options, so if it offers anything sounding performance enhancing, I've not selected it. I have to say I hate the bios layout of the motherboard as it makes it hard to find anything, and most of it I can't adjust, presumably unless I disable an auto-something elsewhere.

In the end I've backed off the speed to 3100, and so far it has been error free for over two weeks. Elsewhere I was pointed to VCCIO and System Agent voltages, but it was unclear what I should do with them. The bios has set values of 1.785v for both, with system agent measuring 1.224v.

CPU is i7-6700k. I have forced it to not overclock at 4 GHz to eliminate that as a factor.

Any ideas on getting it stable at 3333?

[RogueEric]

I've been looking all over the internet and I think we are having similar issues. I have 2 x 8GB sticks of F4-3400C16-8GTZ and while they look gorgeous, I get Q-Code 55 (no memory installed) and 4F (DXE IPL started) with no POST on about half of my initial cold boots if I have the XMP profile enabled. Continued attempts at rebooting eventually work, with an "Overclock Failed!" message on the POST screen, and the system will stress test fine. I too have the Maximus VIII Hero with the i7-6700K.

This is super annoying and I would love to be able to run at the full 3400Mhz spec speed but for now everything seems stable at plain 2133Mhz.

[porina]

RogueEric have you tried setting XMP then reducing the clock of the ram? I can't see that specific ram part on the motherboard QVL but the QVL also says words to the effect running ram at 3200 or higher depends on the CPU's capabilities. That's in part why I went down to 3100 to test on my system. So 3400 doesn't work, try a bit lower. It's got to be better than 2133, even if not reaching the full speed you paid for.

In my case I'm still wondering if perhaps fiddling with the voltages a bit more could help get 3333 stable, but due to the infrequent nature of the errors it will be a slow process to try guessing blindly without some direction.

[RogueEric]

I'm still ruling out other potential issues but I'm 90% sure now that it is the high clock speed on the RAM that's causing the no-POST. I can see this is going to be a long process, but here we go anyway. When the system boots, it flies.

This is the exact RAM I bought:
http://www.newegg.com/Product/Produc...82E16820231916

And here it is on the QVL:




Here's a couple of related forum posts I've been watching as well:

http://www.tomshardware.com/answers/...ted-speed.html

https://rog.asus.com/forum/showthrea...-when-used-XMP

[porina]

The part you gave before wasn't on the list. I presume that was for the module, not the kit.

Anyway, the bit in red at the bottom of that list is what concerns me. 3200 and faster may depend more on the CPU...

At one of those links was an OG guide, suggesting the VCCIO and SA as set on auto might be on the high side. I could try dropping them some time... see if that helps.

[GSKILL TECH]

Manually input voltage values like DRAM Voltage and System Agent Voltage. Test and see what values are most stable for your particular system.

[porina]

Sounds like a job for later... was rather hoping for more specific guidance on what voltage levels people were ending up with, even if the exact circumstances may vary. I've seen guides elsewhere suggesting turning some up, and then elsewhere saying going too far can work against you too, so it could go either way.

[emissary42]

If you have memory stability issues on a Maximus VIII series board set Maximus Tweak from AUTO to Mode 1 and manually adjust VCCSA and VCCIO. On AUTO both voltages are probably way too high, at least that was the case on my Maximus VIII Gene. How much you have to increase them varies from CPU to CPU, so there is no universal correct value. Just increase them in small steps until you gain full stability. However if even +200mV are not enough it might be something else thats off (i only needed around +120mV with 4x4GB @ DDR4-3333).

Edit: Also updating BIOS might help, since ASUS was improving memory compatibility with the latest releases.

[porina]

Thanks, so I probably should be looking to lower mine as they are on auto at the moment. I think I missed out a zero in one of the voltages I wrote previously. I do recall in bios the description suggested the default was far below where I am now.

I'm also up to date on bios. A little unnerving there's been about 4 since I got the motherboard, and most of them have stability improvements included in the description! Correction, just checked again and there was another update 3 days ago. Description "Improve system stability". Guess that'll be my job on the weekend.

[RogueEric]

Ok...whew...this week has been a journey into the depths of my motherboard lol. Porina, you're right I had a typo in my first post, I was thinking of each stick individually when I should have been thinking of the whole kit.

In any case, here's where I am now, this screenshot was taken after an hour of Realbench stress test and then one pass of the benchmark:



Here's how I got here.

Update Maximus VIII Hero to BIOS 1102

1. Enabled XMP profile, takes RAM to its XMP timings and 3400Mhz and BClk to 102.1.

2. Reduced RAM clock to 3000Mhz, kept XMP timing

3. Reduced Bclk to 100

4. Increased Core ratio to 46, sync all cores

5. Minimum cache ratio to 41, Maximum to 46

6. VCCIO to 1.2

7. System Agent to 1.25

8. DRAM voltage to 1.36 (1.35 is what comes with the XMP profile)

9. CPU core voltage to 1.36, Manual for stressing, Adaptive otherwise

Everything else is in stock or Auto settings.

Let's see if she keeps booting through the weekend. Fingers crossed.

[kaan]

With many people attributing shutdowns/errors to other things, I don't think XMP is working for a lot of people, from my experience it was a fiasco and as I see it's the same for many others

It's better to just manually overclock things, in almost all situations manual overclocks are cooler and more stable than Auto BIOS values

It's also a shame that everyone suggests increasing IO/SA voltages, yet there absolutely none suggested values for any CPU, with my motherboard, an MSI Z170I, I can't read IO/SA/GT, I can only set them blindly, it's also unclear whether setting a value is better than Auto

I will follow this thread, as I also have an 6700K and XMP issues

Out of curiosity, how are your 6700K temps under load and does XMP bump up this temps?
(For me, XMP seriously increased this temps, I initially saw 90C's etc, wish I was wise enough to take over when I first built my system, currently, with manual settings, at high load temps are at 61C's, around 50C's at gaming etc.)

[RogueEric]

I'm going to be playing with settings all weekend to see if I can isolate a single factor that's causing the heat and instability. With the settings I mentioned in the previous post, I'm just under 70C under stress testing and no higher than mid fifties while gaming, but this is with a Predator 240 with an aggressive fan curve (sound canceling headphones for the win!). Stay tuned.

[RogueEric]

This just in, new Maximus VIII Hero BIOS version 1202 is out now. I'll be flashing it tomorrow morning.

[porina]

1102 released just 4 days earlier must have been good then... just as well I didn't have time to update yet. I think I'll defer tinkering for a week just in case as I've got a busy weekend ahead. Edit: I just noticed that 1202 has a beta tag over it.

My CPU temps are typically 55C ball park depending on house temperature. It is slightly cooler this morning around 50C. This is under sustained load conditions, and I have the Corsair H110i GTX watercooler. Currently running 4.2 GHz auto voltage, whatever that is.

[RogueEric]

1202 is going strong for me so far, it might be beta but its working great for me minus the whole can't get to the advertised XMP speeds. I'm keeping a text log of all the profiles I've used. Still only can boot when the RAM is set to 3000Mhz or less.

Google Drive link:

https://drive.google.com/folderview?...1E&usp=sharing