Yes, the Vtt-DDR needs to be specifically matched to the VDIMM.
Yes, the Vtt-DDR needs to be specifically matched to the VDIMM.
I've faced difficulties for years trying to boost my memory speed on this system. I assumed the Vtt-DDR should be configured at 0.5 VDIMM. But my Taichi z390 actually raises the voltage by 0.025V and doesn't seem to have any sensors to show Vtt-DDR readings. I had believed I needed more VDIMM even though I was already above 1.6V for a specific configuration. Despite giving up, since there were no sensors tracking Vtt-DDR, I decided to experiment with different values. The BIOS required a VDIMM setting of 1.575 (measured as 1.6V by HWiNFO64), which was nowhere near the 0.5 VDIMM I was aiming for. After testing from 0.7V upwards, I set Vtt-DDR to 0.76V. This adjustment seems to have resolved all my issues. It's hard to believe how sensitive everything is. Is Vtt-DDR really that crucial or affected by VDIMM? Could the Asrock z390 Taichi also overvolt the Vtt-DDR?
The 1.6v for the RAM seems excessive, possibly due to your IMC preferences or the ICs in your RAM not being properly matched. The optimal range for CoffeeLake was around DDR4-3200MHz to DDR4-3600MHz with minimal latency. Going beyond that likely caused overheating or added unnecessary stress, especially if the cost increased significantly. Could you share the RAM model and your motherboard's BIOS version?
Lutfij is entirely accurate. The specification for 9th Gen processor memory voltage is 1.35 ± 5%, reaching a maximum of 1.416 at the IMC on the CPU die. Because BIOS cannot select a precise value of 1.416, any VDIMM above 1.42 is excessive and may lead to instability and permanent damage to the IMC. Clearly, 1.6 is WAY TOO HIGH! Refer to page 139, 9th Generation Intel® Core™ Processor Families Datasheet, Volume 1.
4000Mhz RAM speeds don't matter much for Coffeelake. There are many cases where people reach 4500Mhz, especially with Coffeelake. The VDDQ mentioned isn't the actual voltage. I found the highest recommended VDIMM from a guide here: https://github.com/integralfx/MemTe...OC Guide.md#maximum-recommended-daily-voltage. Also, according to Thaiphoon Burner, my F4-4266C17D-32GVKB 32 GB G.Skill Ripjaws V uses a Samsung B-die: 8 Gb B-die (Boltzmann / 20 nm) per die.