Question Please Help me understand performance of these RAM choices

[Caveman]

The first is 32GB total, and the 2nd is 64GB total. The flight sim and CAD applications the machine is being built for will probably use more than 32 GB 10% of the time. Aside from the larger amount giving an assumed better performance overall, which RAM would be expected to perform faster and why? The first has a CL of 36. The second is 40. I'd assume lower CL is faster but the PC5 numbers confuse that assumption (the 40 CL has a higher PC5 number). And... is lower voltage of the first kit better than higher voltage of the 2nd kit?


1) CORSAIR Vengeance RGB 32GB (2 x 16GB) 288-Pin PC RAM DDR5 5600 (PC5 44800) Desktop Memory Model CMH32GX5M2B5600Z36K

• DDR5 5600 (PC5 44800)
• Timing 36-36-36-76
• CAS Latency 36
• Voltage 1.25V

2) CORSAIR Vengeance RGB 64GB (2 x 32GB) 288-Pin PC RAM DDR5 6000 (PC5 48000) Desktop Memory Model CMH64GX5M2B6000C40

• DDR5 6000 (PC5 48000)
• Timing 40-40-40-77
• CAS Latency 40
• Voltage 1.35V

 

[igor_kavinski]

RAM Latency Calculator

Latency wise, DDR5-5600 kit seems faster but bandwidth wise, DDR5-6000 will be better for overall performance.

 

[igor_kavinski]

These 64GB kits are faster:

Are you a human?

www.newegg.com

Are you a human?

www.newegg.com

 

[Caveman]

Thanks for the NewEgg links. That GSkill RAM is of interest. From the post above with the calculator, the 64GB set appears to be 3% slower but in practical use in a loaded situation where 64GB are called for, the additional speed from the throughput would be noticeable?

I noticed the GSkill RAM runs at a slightly higher voltage. I'm assuming less voltage required implies some inherent stability all other variable being equal?

 

[igor_kavinski]

Less voltage RAM would be less of a drag on the integrated memory controller of the CPU and I guess more stable.

On the Intel side, you will probably need a K series CPU for anything above the 1.25V kit. Thankfully, Ryzens are not market segmented like this, yet.

Any benchmark or game or application that needs a LOT of data to process through, will need more bandwidth than latency so the higher speed with higher latency may trump lower speed RAM with lower latency, as long as the difference in absolute latency calculated using the memory latency calculator isn't too high. For instance, 5 ns slower higher speed RAM may just perform as well as 5 ns faster lower speed RAM. In general, it is best to go with highest speed with lowest latency so DDR5-6000 with CL30 would be the best kit.