Memory Can't Reach Spec: 3000 MB/s

[jchunter]

I had printed out the QVL and just noticed the memory timing is a bit different from that in my bios (15-17-17-35 vs. 15-15-15-36). Might be a good idea to try the QVL timing?

 

[ATMINSIDE]

You can try it, but those timings are tighter and therefore are more likely to have issues.

 

[jchunter]

You can try it, but those timings are tighter and therefore are more likely to have issues.

I set up the QVL memory sub timing at 2900 MHz, 1.35v but it crashed also. Stay tuned...

 

[Woomack]

On Z170 motherboards a lot depends from BIOS and memory profiles. Corsair memory for some reason works not so good on Z170. I don't know if they sell kits designed for X99 or something else.
Anyways, VCCSA is not required to be set above stock up to 3200+. If it works on 2 modules then on 4 it should work too. At least up to ~3400 shouldn't be big issues.

Check something like:
3000 15-16-16-36 2N 1.35V tRFC 420
3000 16-16-16 ....
3000 16-17-17 ....

Can also check if mobo has any memory profiles and try them.

 

[jchunter]

On Z170 motherboards a lot depends from BIOS and memory profiles. Corsair memory for some reason works not so good on Z170. I don't know if they sell kits designed for X99 or something else.
Anyways, VCCSA is not required to be set above stock up to 3200+. If it works on 2 modules then on 4 it should work too. At least up to ~3400 shouldn't be big issues.

Check something like:
3000 15-16-16-36 2N 1.35V tRFC 420
3000 16-16-16 ....
3000 16-17-17 ....

Can also check if mobo has any memory profiles and try them.

Sorry for the long delay in answering. I just received replacement Corsair cmk16gx4m4b3000c15 memory sticks from NewEgg RMA.

Unfortunately the new sticks behave just as the last ones did: They are very stable at stock voltage at 2800 but crash immediately at 2900 and above on every sub timing that you suggested.

I guess we should start looking at the mobo (Gigabyte ga-z170xp-sli). There are a million bells and whistles in the bios... However, the i7-6700k has always been stable at 4.6ghz. BTW, I did the above testing at 4.5ghz just to lighten the power load.

 

[Woomack]

Most Corsair kits are not working at XMP settings on Z170 boards. At least I see many users complaining about it. Simply you set it manually or look for a different memory brand. I had no issues with G.Skill Ripjaws V and Trident Z. Also Geil Dragon ( DDR4-3333 kit ) and lower frequency Kingston and EVGA kits were working fine.

 

[jchunter]

Good news: Corsair DDR4 Memory now works at XMP rating 3000 and passes short stability tests.

This was accomplished with the good advice of Arturo, in Corsair Tech Support, who suggested trying Gigabyte Bios release F5a (beta). I had ignored F5a because it was older than F5, which I was already using. The XMP settings as displayed in the bios are 3000 GHz, Vmem=1.2v*, sub timing 15-17-17-35, tRFC=390. I have not tried setting these manually in bios F5, yet.

BTW, under F5a, the Intel ETU displays different memory parameter values than the bios, so IMHO, there is still some development work to be done in this beta release...

* Edit: Vmem displays 1.2v in F5a bios "Advanced Voltage Settings" but displays 1.368v in bios "PC Health Status/DRAM Channel A/B..."