Question Unable to run ddr4 3200MHz rated quad modules on dual channel mode anywhere above 800Mhz

[SaM_SpArK]

Mobo : Asus Maximus VIII Hero
CPU : Intel Core i7 - 6700K ( Max DDR4 frequency supported without XMP is 2400mhz according to intel specs )
Chipset : Z170
Ram : 4 * 8 GB Corsair VENGEANCE RGB PRO DDR4 ( cmw16gx4m2c3200c16 ) // Two modules got Sk chips and other two have Samsung

Simply it won't execute normal boot with cleared CMOS and MemOK function is needed to set timings, MemOK automatically enables XMP and loads 3200MHz XMP profile but DDR frequency must be set on 1600MHz, So each module runs on 800MHz ( dual channel DDR ) and it POSTS anything higher than 1600hmz fails to POST with Q-Code 55

As far as i know 32Gb is supported on the mobo and cpu and there shouldn't be a problem with quad module running in dual channels ??!!
Performance benchmarking shows significant reduction in scores comparing with dual module installed and run at 3200MHz and laggy windows explorer

Info is added by screen shots

 

[Lutfij]

Ram : 4 * 8 GB Corsair VENGEANCE RGB PRO DDR4 ( cmw16gx4m2c3200c16 ) // Two modules got Sk chips and other two have Samsung
What are the PCB revisions for both ram kits?

 

[RealBeast]

It sounds like you used two different sets. Even two different sets of the same model often does not work because it was not factory tested and the very minor differences cause instability, which results in either not running at all or running slower. Back in the day you could pretty much get any two modules to work together. Those days are long gone.

 

[35below0]

Maximum supported speed without XMP (by the motherboard) is 2133Mhz.

Check that all modules have the same latency. Seems so, but check anyway.

That Corsair is not listed as supported @3200Mhz. Only 4x4Gb (16Gb) is supported.

Fastest DDR4 you can run on that motherboard is 3466Mhz 4x4Gb.
Fastest rate for 32Gb is 2800Mhz, 4x8Gb.

 

[SaM_SpArK]

Ram : 4 * 8 GB Corsair VENGEANCE RGB PRO DDR4 ( cmw16gx4m2c3200c16 ) // Two modules got Sk chips and other two have Samsung
What are the PCB revisions for both ram kits?

I can't find that stated anywhere

 

[SaM_SpArK]

Maximum supported speed without XMP (by the motherboard) is 2133Mhz.

Check that all modules have the same latency. Seems so, but check anyway.

That Corsair is not listed as supported @3200Mhz. Only 4x4Gb (16Gb) is supported.

Fastest DDR4 you can run on that motherboard is 3466Mhz 4x4Gb.
Fastest rate for 32Gb is 2800Mhz, 4x8Gb.

they Can't even be run @ 2400 anything other than 1600mhz make it unable to get a POST

 

[35below0]

That kit is not compatible so it will run at whatever fallback speed exists, if it runs at all. In your case, it runs at 1600Mhz
Replace with a kit that is supported?

 

[SaM_SpArK]

It sounds like you used two different sets. Even two different sets of the same model often does not work because it was not factory tested and the very minor differences cause instability, which results in either not running at all or running slower. Back in the day you could pretty much get any two modules to work together. Those days are long gone.

that would have been even good to downclock them near 2800-3000mhz but this 1600mhz seems to be problematic even visually

 

[35below0]

that would have been even good to downclock them near 2800-3000mhz but this 1600mhz seems to be problematic even visually

Only the 4x4Gb kits can run at 3200Mhz i'm affraid.

 

[boju]

Have you tried only running two sticks with same ICs?

 

[35below0]

Have you tried only running two sticks with same ICs?

4x4Gb @3200Mhz single sided Corsair is supported. 4x8Gb @3200Mhz is not.
More to the point, the RGB Pro RAM is not supported. LPX is on the compatibility list and the manual says it's compatible.

Two sticks or four, that RAM will not run at it's stock 3200Mhz on that motherboard, but at a fallback rate.

 

[SaM_SpArK]

Have you tried only running two sticks with same ICs?

Yes, Works fine

 

[SaM_SpArK]

4x4Gb @3200Mhz single sided Corsair is supported. 4x8Gb @3200Mhz is not.
More to the point, the RGB Pro RAM is not supported. LPX is on the compatibility list and the manual says it's compatible.

Two sticks or four, that RAM will not run at it's stock 3200Mhz on that motherboard, but at a fallback rate.

a fallback to 1600mhz seems unresonable and compatibility list is a bit old

 

[boju]

Yes, Works fine

Yeah i thought they would, also Corsair have their own updated motherboard support list and your ram is included. DDR3 back in the day you had a higher chance mixing ram and not be penalised. DDR4 can be very fussy, more so with different ICs between sets, that increases fussiness even further.

Not sure how much further you can go from here, i guess you could try your luck manual setting rather than use XMP preset and tinker with timings and adding a little more voltage. Four sticks can also be a dilemma in itself which can be problematically straining on CPU memory controller. I'd say not waste your time, return those and opt for a pair of 16GB sticks instead

 

[SaM_SpArK]

Yeah i thought they would, also Corsair have their own updated motherboard support list and your ram is included. DDR3 back in the day you had a higher chance mixing ram and not be penalised. DDR4 can be very fussy, more so with different ICs between sets, that increases fussiness even further.

Not sure how much further you can go from here, i guess you could try your luck manual setting rather than use XMP preset and tinker with timings and adding a little more voltage. Four sticks can also be a dilemma in itself which can be problematically straining on CPU memory controller. I'd say not waste your time, return those and opt for a pair of 16GB sticks instead

yeah I guess, for sake of knowledge could memory controller be affected by populated Pcie slots ? looks like I'm pushing my CPUs direct PCIe bandwidth to a limiting factor on my NVMe drives performance

 

[boju]

yeah I guess, for sake of knowledge could memory controller be affected by populated Pcie slots ? looks like I'm pushing my CPUs direct PCIe bandwidth to a limiting factor on my NVMe drives performance

6700k has 16 pcie lanes which are prioritised for pcie slots, your Nvme drives run off motherboard chipset so no stress on your cpu. Nvme communicating directly to cpu began with 11th gen for Intel with 20 pcie lanes, the additional 4 for M2 pcie.

 

[SaM_SpArK]

6700k has 16 pcie lanes which are prioritised for pcie slots, your Nvme drives run off motherboard chipset so no stress on your cpu. Nvme communicating directly to cpu began with 11th gen for Intel with 20 pcie lanes, the additional 4 for M2 pcie.

Looking at 2016 rev of Asus manuals describes 3 slots out of 6 slots as CPU_PCIe and 3 other as PCH_PCIe
also device manager shows drivers for PCIe bus manager and another driver for PCH PCIe bus manger, or I'm just messing it up all in my mind 😵

 

[boju]

MAXIMUS VIII HERO｜Motherboards｜ASUS Australia

www.asus.com

• 2 x PCIe 3.0 x16 slots (CPU)
  3 x PCIe 3.0 x1 slots (PCH)
  1 x PCIe 3.0 x16 slot (PCH)

The two gray pcie slots are connected to cpu, x8 x8 if both are occupied. Rest chipset, Z170 has 20 PCH lanes.

https://www.pugetsystems.com/labs/a...umber and speed of,the slower PCIe 2.0 speeds.

 

[RealBeast]

that would have been even good to downclock them near 2800-3000mhz but this 1600mhz seems to be problematic even visually

What I'm actually saying is that you are lucky they even post, much less run at any speed. The Memory QVL for your board stops at 3000, no 3200 sets, and only one Corsair set that will do 4x8GB at 3000.