Crucial Pro DDR5-5600 CL46 64 GB Review

Name: Crucial Pro DDR5-5600 CL46 64 GB
Brand: Crucial
Price: 150 USD

ir_cow

on Nov 27th, 2024,

in Memory.

Manufacturer: Crucial

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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 an 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 an 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 no 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 an 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 revisions start at DDR5-8000 and can reach up to DDR5-9000+ with exotic cooling such as LN2.

Now with Intel Ultra 200 series and Socket 1851, memory support has extended either further with DDR5-9000+ using the new CUDIMMS.

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.

Spoiler: AMD DDR5 Tweaking

When it comes to overclocking, things get a little bit complicated trying to understand all the technical terms and how they fit together. With the new AM5 socket, AMD has switched to DDR5 exclusively, leaving DDR4 behind. Those familiar with the ideal configuration from the previous platform can still apply some of the same overclocking principles here as well. Those new to the memory overclocking scene or need a refresher only need to follow a few rules to get started.

First is a quick refresher for AMD and DDR4. The ideal configuration for Zen 2 (3000 series) and Zen 3 (5000 series) based processors will always be to match the internal Infinity Fabric (IF) to the memory controller, which matches the frequency of the system memory as well. This is often referred to as a 1:1:1 configuration. Once the system memory exceeds the capabilities of the memory controller, a secondary system is in place to allow the memory to still function and operate by breaking this ratio. In doing so, the memory controller frequency is now cut in half, operating in a 2:1 configuration. This introduces a major latency penalty that negatively effects games that are memory sensitive with a measurable frame rate loss in some instances. AMD marketing uses DDR4-3600 as the "sweet spot" for Ryzen 3000 series, with DDR4-3800 best suiting Ryzen 5000 series processors. This is where cost vs. performance intersects, giving good results by using just X.M.P (A-XMP, DOCP, EOCP) DDR4-3600 profile and the motherboard auto settings. For the most part, this is a set and forget type of situation using single or dual-rank memory in the system for a total of two DIMMs. In the example above, DDR4-3600 in a 1:1:1 configuration would be 1800 MHz for all three. Generally speaking, ignoring outliers, 2000 MHz IF and DDR4-4000 RAM is the upper limit for this ratio when using an AMD Ryzen 5000 processor.

With the basics out of the way, we can talk about DDR5 and what to expect now that this AMD (AM5) platform uses it exclusively. The AMD engineering team has changed the formula slightly from the ideal DDR4 configuration. The new "sweet spot" is now DDR5-6000, but with a twist. The Infinity Fabric (FCLK) is now independent and no longer is required to match the system memory for best results. In many instances a FCLK of 2000 MHz is the default value with a range "up to" 2133 MHz. It is highly suggested to leave this value at 2000 MHz, as higher frequencies often will outright refuse to work with a system hard-lock, requiring clearing the CMOS to recover. Even though some motherboard manufacturers have cited 2133 MHz as a possibility in media review guides, it may not be until the next CPU generation when we achieve these numbers consistently, without the aid of binned CPUs.

During the testing phase of different AMD motherboards and from observation while working on these reviews, it seems that for now DDR5-6400 and beyond will be out of reach for many users in a memory ratio of 1:1. AMD AGESA / BIOS updates have increased compatibility. The standard setup of a 2000 MHz 1:1 ratio works well through DDR5-6000. While a wide range of AM5 B650 / X670 / X870 motherboards support DDR5-6400+, this frequency and above can be problematic without some manual intervention for motherboard settings. Often lowering the FCLK and / or changing the memory ratio to 2:1 (Gear 2) will help alleviate some configurations that are struggling to get fully stable.

Caution is advised with raising DRAM voltage over the rated EXPO / XMP profile. Direct airflow may be necessary for long-term stability. This extends to the CPU as well. Raising the integrated memory controller voltage above AMD 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.

The common expectation for memory overclocking in a review is to go for the highest possible frequency, which then is used to gauge how "good" the memory is overall. This can be misleading, as each memory kit will differ per batch to a certain degree. Secondly, this data does not benefit the majority of users who do not have the required computer components to reach these same overclocking values. Instead, in this section going forward, we will pit memory that has the basic XMP profiles applied to ones that are manually adjusted at using the same frequency. This means all the sub-timings not included in the SPD data are set by the motherboard. This is how the benchmarks are complied by. Next we adjust the sub-timings to relatively low values without changing the XMP primary timings or voltage. Lastly, we adjust the CAS values along with the previous sub-timings and raise the voltage (if necessary) to accomplish this. These individual settings can be found in the image gallery below.

Before we continue further, there are a few quick observational notes related to the secondary and tertiary timings. For the most part, these values are limited by the type of memory ICs, revision, and/or its "quality," along with the signal integrity of the motherboard traces and trace length. Overall, with the exception of tRFC(1,2,SB) values and tREFI which are both highly dependent on temperature, the rest have a rather low factor for temperature sensitivity. In which neither a bump in DRAM voltage nor an operating temperature between 43-53°C will factor into the lowest these values can be set to.

Intel Results

Following the same overclocking procedures as the previous reviews, a tedious, methodical process of changing each value and validating if, in fact, it was stable for long periods of time. This does not guarantee 24/7 stability, but it is enough for a normal home computer use-case. These results below were validated to pass y-cruncher 2.5B and reach 6000% or higher in the memory stress testing software Karhu. Because of this longer stability test, temperatures can become a big factor. This often requires the sub-timings to be adjusted to withstand the heavy stress placed upon the memory during validation. Some additional small adjustments could have been made to the secondary and tertiary timings, but the gains would be minimal and likely harder to stabilize in the long run.

Micron already has a reputation for limited overclocking potential, and by sticking with the XMP/EXPO profile 1.1 V compliance, the highest frequency wouldn't be much of an adventure. Instead, we opted to reach the highest frequency with 1.35 V. This is because, firstly, 1.1 V isn't enough to do much of anything remotely considered an overclock. Lastly, increasing voltage for Micron ICs beyond 1.35 generally has a negative impact on stability and could outright kill the ICs before the overclocking even began.

With that said, the first stop was reaching the highest this memory kit could go using only 1.35 V. This ended at 6400 MT/s. Setting the Primary Timings and tRFC values even looser did not yield anything greater and refused to post. The next step was to lower the primaries to the lowest they go until it no longer posted (not much at all). Once that was found, the final step was to work on the sub-timings. All of which to a non-seasoned overclocker may seem quite loose, but Micron ICs do not play nice in comparison to Samsung; with SK Hynix being the gold standard. Even though Micron Rev D is supposed to be better, the sample in this review is loser in the lottery. Regardless of the revision, they don't play nice when overclocking and is why you (currently) will not find Micron in high frequency memory kits (yet) or in any overclocking records.

Baldur's Gate 3 Results

Counter-Strike 2 Results

Remnant 2 Results

AMD Results

Over on the AMD test bench, overclocking this memory turned out to be not an easy conversion from Intel. Most of the same sub-timings were simply not stable (or post), though it is expected to be different nonetheless. In the end, a compromise was made. Instead of starting completely over, many of the values from the motherboard's applied timings were left unchanged. Even so, the few values that did work, could not be set as low in comparison to the Intel system.