CPU and RAM overclocking
CPU and RAM overclocking
Hello everyone, I'm trying to figure out why my I5 6600k won't let the RAM voltage be set to 1.35. I've overclocked the CPU to 4.1, but I'm not sure if going higher is necessary or if it affects things. Also, I can't use the XMP profile without it crashing. I have the i56600k, z170pro gaming, and a 4x4 Corsair Vengeance 16GB RAM at 300MHz with 1.35V. Thanks for your help!
No, the RAM frequency these sticks come with is based on an XMP profile, which isn't active until you enable XMP in BIOS. The RAM can operate at various speeds, both slower and faster, by modifying timings and adjusting the DRAM voltage within certain limits. This approach is safe as long as temperatures remain acceptable for both RAM and CPU (which is manageable with DDR4), or if the DRAM voltage stays below 1.5V (as specified by Intel). Most users don’t need to worry about voltages above 1.4V, since that’s the maximum setting in XMP profiles. The only issue arises when experimenting with settings that cause instability.
Set up the following voltages:
- VCCSA (System Agent Voltage) to 1.1V (Manual mode)
- VCCIO to 1.1V
- VTTDDR to half of the DRAM voltage
If this doesn’t work, attempt to increase the memory speed from 3000MHz to 3200Mhz and adjust the timings to match a RAM kit with 3200MHz XMP from the same brand.
It may seem unusual, but this might be a compatibility concern rather than an unstable overclock. This has functioned before. 3000MHz often leads to problems on Z170 and X99, so I usually suggest 3200MHz instead.
Additionally, sometimes the CPU needs to be overclocked to a higher frequency for higher bandwidth RAM to perform well; 4.1GHz might not be sufficient. Please check compatibility first.
Ensure you configure these voltages:
- VCCSA (System Agent Voltage) to 1.1V (Manual mode)
- VCCIO to 1.1V
- VTTDDR to half the DRAM voltage
If this doesn’t work, attempt to raise the memory speed from 3000MHz to 3200Mhz and adjust the timings to match a RAM kit with 3200MHz XMP from the same brand.
It might seem unusual, but this could be a compatibility problem rather than an unstable overclock. This has been successful before. 3000MHz often causes issues on Z170 and X99, so I usually suggest 3200MHz instead.
Also, sometimes you need to increase the CPU frequency to a certain level for higher bandwidth RAM to function properly; 4.1GHz might not be enough. Please check the compatibility first.
The RAM speed settings listed on the stick listings are merely an XMP profile, which isn't activated until you enable XMP in the BIOS. The RAM can operate at various speeds, both lower and higher, by modifying the timing and DRAM voltage settings (within certain limits).
This approach doesn’t pose a risk to the RAM modules as long as temperatures remain acceptable for both RAM and CPU (which is manageable with DDR4 RAM), or if the DRAM voltage stays below 1.5V (as recommended by Intel). This voltage threshold helps protect the CPU’s memory controller, although most users stay below 1.4V since that’s the highest setting in XMP profiles.
The only issue arises when attempting unstable settings during startup, which can prevent BIOS from booting and may require resetting the CMOS battery on the motherboard to restore stability (unless using an Asus motherboard with MemOK). This detail is best left for further discussion.
Regarding compatibility, there are various RAM speed options depending on the motherboard’s support. If a particular speed isn’t supported, it won’t appear in the BIOS settings.
Compatibility also extends to the chipset and RAM modules together. The X99 and Z170 chipsets may not work well with certain high-speed RAM (generally between 2800MHz and 3000MHz), especially when overclocking or using many RAM slots. This instability can sometimes manifest as a blue screen before all RAM sticks fail, leading to system crashes until the issue is resolved.
Additionally, there are rarer speeds like 2600MHz, 2800MHz, 2933MHz, and 3466MHz that some motherboards might support, but there’s no guarantee these will function properly with the RAM sticks, even with adjusted timings and voltages.
steffeeh :
No, the RAM frequency the sticks are sold at are just an XMP profile, that won't be used until you've enabled XMP in BIOS - the RAM can run at multiple speeds, both lower and higher, given that you adjust timings and the DRAM voltage accordingly (to a certain limit of course).
This isn't dangerous for the RAM sticks as long as the temperatures are good on both RAM and CPU (which is no problem for DDR4 RAM), or as long as the DRAM voltage is below 1.5V (specified by Intel) as it can otherwise degrade the memory controller on the CPU. Though most people no longer feel comfortable above 1.4V, as it's the highest voltage setting found in XMP profiles.
The only uncomfortable thing is that if you try out a settings that goes unstable right when the computer boots, then BIOS won't boot since it can't find the RAM, and then you need to pick out a battery (called CMOS) from the motherboard to reset everything in BIOS so all settings are stable again (unless you have an Asus mobo which has a feature called MemOK, which is why I always go with Asus mobos). Though no need to dive into this here as it's a subject of its own.
As for compability, you could say there are different types of compabilities. What you're referring to is the motherboard's supported RAM speeds - if it's not supported that means you won't even find that speed option in BIOS.
What I'm referring to is compability with the chipset together with the RAM sticks. X99 and Z170 chipsets are known to become incompatible with certain RAM speeds (mostly from 2800MHz to 3000MHz, with 2666MHz and 3200MHz also being unreliable sometimes, but rarely) when you overclock the CPU and/or fill out most RAM slots. This can even take sometime before you get a bluescreen, as everything is fine at first, but then one stick after the other disappears, until all RAM is lost and the system crashes.
More than this, you also have the more uncommon RAM speeds, such as 2600MHz, 2800MHz, 2933MHz, 3466MHz etc, which may be supported by the motherboard, but there's no guarantee that the RAM sticks themselves will work with it - despite edited timings and voltages.
I really appreciate your time in helping me, this is all very helpful! thank you very much