Have to continually increase VCCIO in order to pass POST with XMP memory settings

[THX1139]

In order to use my memory at its rated speed using the XMP settings, it has been necessary to increase my system agent voltage and my VCCIO voltage. The problem I seem to be experiencing is that increasing the VCCIO has enabled passing the POST but subsequent POSTs fail and I have to increase the VCCIO again. My concern is that increasing the VCCIO is causing some kind of damage which must be overcome by further increasing the VCCIO. Is this a known issue?

Right now I've disabled XMP so my memory is underclocked.

Last time I POSTed at VCCIO 1.16 V but later failed to POST even at 1.17 V. The font colour in the BIOS is red for voltages above 1.09 V so I'm hesitant to just keep increasing it.

OS: Win 10 Pro 64-bit
Mainboard: ASUS Z170 Pro Gaming, board revision 1.04, BIOS v3501
CPU: Intel i7 6700, Stock HSF, Undervolt Offset -0.075 V, VCCIO 1.16 V, System Agent 1.15 V, LLC 4 (all core enhancement DISABLED)
RAM: Corsair LPX Vengeance 2x8GB DDR4-3000 (CMK16GX4M2B3000C15), XMP
Graphics: Gigabyte NVIDIA GeForce GTX 950 w/ 2 GB
Sys Drive: Samsung Evo 750 SSD, 250 GB
Data Drives: OCZ Vertex 2 SSD, 60 GB; WDC WD1002FAEX-00Y9A0, ~1 TB; WDC WD2003FZEX-00Z4SA0, ~2 TB; WDC WD2002FAEX-00MJRA0, ~2 TB; RAID 0, ~300 GB [Maxtor 6B160MO x 2]
PCI-E SATA expansion: IOCREST SATA III 4-port PCI-e (SI-PEX40064)
PSU: XFX TS 750W (P1-750S-NLB9)
Bluetooth: Parani UD100 Bluetooth USB Adapter
Monitor: LG 21.5" W2246S-BF 16:9 Wide LCD Monitor 1920x1080 5ms
Logitech G500 mouse, K120 keyboard.

UEFI BIOS divergence from optimised default settings
AI Overclock Tuner [Auto]->[XMP]
DRAM Frequency [Auto]->[DDR4-3000 MHz]
Min. CPU Cache Ratio [Auto]->[40]
Max CPU Cache Ratio [Auto]->[40]
CPU Core/Cache Voltage [Auto]->[Offset Mode] (-0.075)
CPU VCCIO Voltage [Auto]->[1.09 V]
CPU System Agent Voltage [Auto]->[1.05 V]
DRAM Voltage [Auto]->[1.350]
DRAM CAS# Latency [Auto]->[15]
DRAM RAS# to CAS# Delay [Auto]->[17]
DRAM RAS# ACT Time [Auto]->[35]
CPU Load-line Calibration [Auto]->[Level 4]
SATA Mode Selection [AHCI]->[RAID]
Model Name LED Lighting [Breathing Mode]->[Disabled]
SupremeFX LED Lighting [Breathing Mode]->[Disabled]
CPU Q-Fan Control [Auto]->[PWM Mode]

[Silent_Scone]

THX1139 wrote:
In order to use my memory at its rated speed using the XMP settings, it has been necessary to increase my system agent voltage and my VCCIO voltage. The problem I seem to be experiencing is that increasing the VCCIO has enabled passing the POST but subsequent POSTs fail and I have to increase the VCCIO again. My concern is that increasing the VCCIO is causing some kind of damage which must be overcome by further increasing the VCCIO. Is this a known issue?

Right now I've disabled XMP so my memory is underclocked.

Last time I POSTed at VCCIO 1.16 V but later failed to POST even at 1.17 V. The font colour in the BIOS is red for voltages above 1.09 V so I'm hesitant to just keep increasing it.

OS: Win 10 Pro 64-bit
Mainboard: ASUS Z170 Pro Gaming, board revision 1.04, BIOS v3501
CPU: Intel i7 6700, Stock HSF, Undervolt Offset -0.075 V, VCCIO 1.16 V, System Agent 1.15 V, LLC 4 (all core enhancement DISABLED)
RAM: Corsair LPX Vengeance 2x8GB DDR4-3000 (CMK16GX4M2B3000C15), XMP
Graphics: Gigabyte NVIDIA GeForce GTX 950 w/ 2 GB
Sys Drive: Samsung Evo 750 SSD, 250 GB
Data Drives: OCZ Vertex 2 SSD, 60 GB; WDC WD1002FAEX-00Y9A0, ~1 TB; WDC WD2003FZEX-00Z4SA0, ~2 TB; WDC WD2002FAEX-00MJRA0, ~2 TB; RAID 0, ~300 GB [Maxtor 6B160MO x 2]
PCI-E SATA expansion: IOCREST SATA III 4-port PCI-e (SI-PEX40064)
PSU: XFX TS 750W (P1-750S-NLB9)
Bluetooth: Parani UD100 Bluetooth USB Adapter
Monitor: LG 21.5" W2246S-BF 16:9 Wide LCD Monitor 1920x1080 5ms
Logitech G500 mouse, K120 keyboard.

UEFI BIOS divergence from optimised default settings
AI Overclock Tuner [Auto]->[XMP]
DRAM Frequency [Auto]->[DDR4-3000 MHz]
Min. CPU Cache Ratio [Auto]->[40]
Max CPU Cache Ratio [Auto]->[40]
CPU Core/Cache Voltage [Auto]->[Offset Mode] (-0.075)
CPU VCCIO Voltage [Auto]->[1.09 V]
CPU System Agent Voltage [Auto]->[1.05 V]
DRAM Voltage [Auto]->[1.350]
DRAM CAS# Latency [Auto]->[15]
DRAM RAS# to CAS# Delay [Auto]->[17]
DRAM RAS# ACT Time [Auto]->[35]
CPU Load-line Calibration [Auto]->[Level 4]
SATA Mode Selection [AHCI]->[RAID]
Model Name LED Lighting [Breathing Mode]->[Disabled]
SupremeFX LED Lighting [Breathing Mode]->[Disabled]
CPU Q-Fan Control [Auto]->[PWM Mode]

VCCSA should take precedence over IO as it's the voltage for the memory controller. For those speeds, a value of 1.15v should be sufficient. More may be needed depending the quality of the CPU IMC.

[THX1139]

Thanks! It seems the system agent voltage was what needed attention!

[THX1139]

Okay, now I seem to be having the same problem again. This time with VCCIO set to 1.16 V and System Agent set to 1.18 V, the system doesn't boot. I'm afraid to keep increasing because it seems to me like I have to increase it on each boot in order to overcome some sort of damage caused by the previous increase and I can't keep increasing it forever.

[Silent_Scone]

THX1139 wrote:
Okay, now I seem to be having the same problem again. This time with VCCIO set to 1.16 V and System Agent set to 1.18 V, the system doesn't boot. I'm afraid to keep increasing because it seems to me like I have to increase it on each boot in order to overcome some sort of damage caused by the previous increase and I can't keep increasing it forever.

Those voltages are within safe ranges for the CPU. Again, every CPU is different in this regard as to what voltage is needed. If the situation improved with more voltage, it may just need a little more (or a little less, both can cause detriment to stability) Remember to test DRAM stability once in the OS, too.