Conclusion
In today’s G.SKILL Trident Z5 CK RGB DDR5-8400 CL40-52-52-134 1.40V 48GB (2x24GB) memory kit review, we took a look at G.SKILL’s flagship Trident Z5 CK RGB memory based on CUDIMM. CUDIMM memory allows higher frequencies on memory modules by use of an onboard clock driver (CKD) chip to moderate the electrical signal of the DIMM. Supported on Intel platforms right now with Intel Core Ultra CPUs and Z890 motherboards, this RAM can enable high frequencies in excess of 8000MT/s+ and 9000MT/s+.
G.SKILL’s Trident Z5 CK memory is exactly this: fast CU-DIMM-based memory. G.SKILL offers five different speeds of this 48GB (2x24GB) memory kit. G.SKILL has a kit of 8200MT/s (CL40-52-52-131), 8400MT/s (CL40-52-52-134), 8800MT/s (CL42-55-55-140), 9000MT/s (CL42-56-56-144) and 9600MT/s (CL46-58-58-153). In today’s review, we specifically looked at the 8400MT/s kit (F5-8400C4052G24GX2-TZ5CRK).
One of the striking and notable features of this series of RAM from G.SKILL is the very mirrored piano black finish on the RAM. It is a deep black and has a very appealing mirrored reflection property to it. It’s a uniquely good look and goes well with many different types of builds or color schemes. In addition, it has customizable RGB with the light bar. As good as the heatsink looks, it is functional as well, being an aluminum alloy and quite large and encompassing, it does an excellent job at keeping the RAM cool at high frequencies. G.SKILL also claims that the memory ICs are hand-picked for quality. These are enthusiast and overclocking-focused RAM modules.
Performance
In our testing, we looked at the default SPD setting of 6400MT/s with timings at CL52-51-51-102. We then tested the two built-in XMP Profiles of Profile 2 at 6400MT/s CL32-39-39-102, which has very tight timings, and Profile 1, which is the intended 8400MT/s at CL40-52-52-134. We also tried out some very simple overclocking by just bumping it up to 8800MT/s at CL42-55-55-141 with no Voltage adjustment. The RAM operated as intended; we didn’t have any issues, even when trying out 8800MT/s overclock.
In our testing, it was very evident that enabling the XMP Profile 2 setting, which keeps the frequency at 6400MT/s but uses much tighter timings, provided a performance advantage that was worth it. This was across the board, whether it be synthetic, rendering or gaming. The real performance advantage came when the intended XMP Profile 1 was enabled at 8400MT/s. There was a clear advantage, in well, everything running at 8400MT/s CL40 compared to the defaults. The memory bandwidth, of course, went way up, and the latency went way down.
Real-world benchmarks like Geekbench showed improvement that was around 7% for different workloads. The largest advantages were seen in rendering applications. Cinebench 2026 improved by 4% and Blender improved by 3-4% as well. V-RAY 6 got an improvement of 4% over default, and we saw some notable improvements in transcoding video times. By far, the biggest performance was in compression performance, where we experienced a 17% performance increase in 7-Zip compression. Of course, AIDA64 memory read bandwidth increased by 27% and, memory write by 16%, and memory copy by 21%.
We also saw an improvement in game performance, depending on the game. One area where the faster memory helped was the 1% Low gaming performance, which improved the experience. In Battlefield 6, utilizing XMP Profile 1 at 8400MT/s improved the AVG FPS by 4% over the default, but the 1% Lows got an amazing 11% performance improvement. Crimson Desert also received a great benefit in gaming with 6% faster AVG FPS and 5% higher 1% Lows. Doom: The Dark Ages was also advantageous, with a 9% performance improvement over default and 5% higher 1% Lows over default.
Final Points
The G.SKILL Trident Z5 CK RGB memory kit represents the flagship memory from G.SKILL, and we can certainly say that this feels like flagship memory. In our testing, the 8400MT/s kit we were testing does provide a nice boost to performance over the default 6400MT/s SPD configuration, and would also be faster than the new 7200MHz default of Intel Core Ultra Plus CPUs as well. There is an advantage here at 8400MT/s over 6400MT’s or 7200MT/s in both content creation and gaming.
This G.SKILL kit at 8400MT/s keeps the timings at CL40 at 8400MT/s, which is pretty good for CUDIMM. It can also support very tight timings at 6400MTs down to CL32. G.SKILL also offers varying kit speeds, from 8200MT/s up to a stellar 9000MT’s and 9600MT/s kits. Though we did not push hard overclocking here, this RAM is geared for enthusiasts and overclockers, and has the potential to achieve higher performance with adjustment and tweaking, at your own risk.
Overall, running at higher XMP settings for RAM, above 6400MT’s or 7200MT’s, upwards of 8000MT/s+, with timings in the lower 40’s, is absolutely advantageous for the Intel Core Ultra and Intel Core Ultra Plus series CPUs for gaming. If you want to get the most out of your Intel CPU, CUDIMM memory is surely the way to achieve that.
