Corsair Vengeance RGB DDR5-7000 CL34 2x 16 GB Review 12

Corsair Vengeance RGB DDR5-7000 CL34 2x 16 GB Review

Value & Conclusion »

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Overclocking Tips and Tricks

Spoiler: Intel DDR5 Tweaking

With testing out of the way, it is time to see if this memory kit has any additional headroom. For Intel, we start off by using the XMP profile and increasing the frequency until the loss of system stability. After finding what can be accomplished without changing any of the timings or voltage, the second step can begin. This is where we go for the maximum frequency and lowest possible timings. Voltage modification above the XMP profile is allowed. After all, this is overclocking!

Intel's 11th Gen Intel Core processor paved the way for things to come. The introduction of the memory controller Gear Ratio allowed the system memory to run in synchronous 1:1 mode (Gear 1) with the CPU memory controller, or in a 2:1 ratio (Gear 2). With the release of Intel's 12th Gen Alder Lake based processors came DDR5 support and the additional 4:1 ratio (Gear 4).

It is generally considered that between 3600 and 4000 MT/s is the upper limit for Gear 1 support when using a Alder Lake (12th Gen Intel) CPU. This of course is partially dependent on the CPU memory controller and supporting voltages related to memory. In rare instances, higher-end motherboards can increase this slightly and offer better overall compatibility due to shorter trace length, higher PCB layer count and a better memory training algorithm. For instance the Intel Core i9-12900K used for these memory reviews maxes out at DDR4 4133 MT/s for single-rank memory. Achieving 4133 MT/s is quite a unlikely occurrence judging based by the sheer number of forum posts of many users struggling to get 3800 MT/s stabilized. It is safe to say that anything greater than 3600 MT/s using Gear 1 will often require a bit of hands-on tuning.

Since DDR5 has a higher operating frequency and a dual 32-bit data bus, synchronously operating it in 1:1 does not function at all. So far there have been no confirmed reports of this working for DDR5. That only leaves 2:1 ratio and above as a viable option for any DDR5-based setups. The motherboard should automatically switch to the 2:1 ratio for both DDR4 and DDR5 above 3600 MT/s. If all else fails, you can manually enforce Gear ratios in the BIOS as well. With this information on hand, we can deduce that Intel 12th generation processors using DDR5 in theory will benefit the most from the highest-possible frequency, until the 2:1 ratio is not longer possible. At that point the cycle starts over again with a new 4:1 ratio and even higher frequency system memory.

Those looking to overclock on a Intel platform will generally find a hard barrier around 6600 MT/s using the Intel Z690 platform and an Intel 12th Gen CPU. Switching to Intel 13th Gen, this value increases to 6800-7200 MT/s when using Intel Z690 motherboards and 7800-8000 MT/s for Intel Z790 4-slot motherboards. Special overclocking specific motherboards like ASUS Z690 Apex, Gigabyte Z690 Tachyon, MSI Z690 Unify-X, ASRock Z690 AQUA OC, and EVGA Z690 Dark can reach up to DDR5-8000+. While the new wave of Z790 versions start at DDR5-8000 and can reach up DDR5-9000+ with exotic cooling such as LN2.

Caution is advised when raising DRAM voltage over the rated XMP profile. Direct airflow or a waterblock may be necessary for long-term stability. This extends to the CPU as well. Raising the integrated memory controller voltage (VDD2), System Agent (SA), and VDDQ_TX above Intel specifications may cause irreparable damage. Please proceed with care and do research before attempting this. Do not copy and paste values without understanding the impact first, especially if simply taken from screenshots posted on Discord or Reddit.

Intel Results


DDR5-7800 Submission Link

This will be the 6th SK Hynix A-Die tested (4th one reviewed). So far they all have been able to reach a 7600 MT/s overclock with various primary timings and voltages. To achieve these results, a direct fan on the memory was needed to pass memory stress tests. It is essential for performance grade memory to have proper cooling. There is certainly a direct correlation to system stability and DRAM temperature that can be made. Lower is always better, and the target goal here is 45°C during load.

Related to system stability and DRAM temperature, those who are tweaking the memory sub-timings may run into problems when maxing out the tREFi value. This is not a good idea without proper cooling such as a waterblock at these higher memory frequencies. Longer periods between cell refresh cycles can lead to data corruption, if not those pesky system errors that are hard to track down. All overclocking here was performed using a spare OS, that if corrupted would not hinder the review process.

With great success previously in the Team Group T-Force Delta RGB DDR5-7200 review, we now have a few targeted goals of 7600 MT/s, 7800 MT/s, 8000 MT/s and 8200 MT/s using a ASUS Z790 APEX motherboard. This ensures that is only limited here is the memory itself. Starting off, the Team Group DDR5-8000 profile was tested, which resulted in errors at 1.45 V around 1500% in the memory test. Raising this to 1.5 V resolved the problems. Instead, 7800 MT/s was used and required no fiddling and used the same XMP profile voltage of 1.45 V. While a desired overclocked frequency is never guaranteed, SK Hynix A-Die does not disappoint. Higher frequencies are achievable by loosening up the timings. Though, by doing so, this negates all benefits of the overclock. Thus, in this case DDR5-7800 was the happy medium for daily usage.






At this juncture, overclocking to these higher frequencies is mostly about doing it because you can. For gaming, this RTX 3080 Ti is the true limiting factor here, leaving the ram to do very little in terms of a real-world benefits outside of benchmarks. As always, it's important to point out that no overclock is ever guaranteed, which makes memory overclocking a new adventure every single time. This also means that the same settings may require more voltage for another kit, or may not be possible depending on the motherboard, CPU and how well the memory performs beyond the rated XMP profile.
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Oct 5th, 2024 16:26 EDT change timezone

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