Patriot Viper Xtreme 5 RGB DDR5-8000 CL38 2x 16 GB Review 21

Patriot Viper Xtreme 5 RGB DDR5-8000 CL38 2x 16 GB Review

Overclocking Part 2 »

Had an Overclocking Dream Lately?

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


DDR5-8200 Submission Link

When all the main testing was done, and it came to the overclocking phase, a dilemma came up. There are two different routes to go, and both completely valid use-cases for this particular memory frequency. The first was to ignore all forms of long-term stability and just go for the limits of the CPU and or memory. The second was to reach what is considered the limits of this CPU IMC using "safe" voltages for daily use. With only time to really explore one option, After some internal debates and monologues, the "safe" route was chosen. The two main deciding factor for this choice was that I didn't want to ruin the CPU that is already a fairly good bin. Secondly, because extreme memory overclocking is outside the reach of many and often needing sub-ambient cooling just to reach these XOC scores, it is too far outside a scope for a standard review.

A risk always exists when overvolting, but it exponentially becomes higher when getting into the red numbers (danger zone). The divide here among overclockers is stability vs highest benchmark score. Simply put, my personal take is if it doesn't pass 25 loops of Memtest5 and y-cruncher 2.5b, that particular memory configuration is not stable. Instability can lead to data corruption, low benchmark scores and just random system stability issues.

With that said, the limits imposed today are not because of the memory. This particular Intel 13900K can run DDR5-8600 with a single DIMM and pass the tests mentioned above. That was achieved with this Patriot Viper Xtreme 5 RGB being reviewed here. Using the 8000 MT/s profile as a base and only needing to increase the DRAM voltage to 1.55, these are quite impressive. For those extreme junkies, DDR5-8800 did boot, but was not fully stable. Though to be fair to Patriot, time wasn't spent on it either.

Back to tweaking this memory. For 8000 MT/s, SK Hynix A-Die is the only type of memory ICs that can reach this without resorting to XOC tactics currently. A small bump to 8200 MT/s and a increase to 1.5 V allowed some sub-timings adjustments. CAS 36 is within reason, but would not pass y-cruncher without a increase to the DRAM voltage even further. Being that this overclock was set up to stay within the confines of "daily use," CAS 38 was kept instead.






Using this memory without additional tweaking still provides great results. However, some minor tweaks to the sub-timings with a frequency increase as well and Doom Eternal gains 8 FPS average. Those who are chasing frames will certainly want to invest time into tweaking the memory, even if you want to stick with 8000 MT/s. 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 a different kit, or may not be possible at all depending on the motherboard, CPU and how well the memory performs beyond the rated XMP profile.
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Aug 25th, 2024 18:20 EDT change timezone

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