Memory Rank Impact on Performance

bigdogchris

bigdogchris

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Written Piece: https://www.techspot.com/article/1971-more-ram-modules-better-for-gaming/

YouTube Version:


BuildZoid Response:


I found this to be an interesting read. OP stating multiple memory ranks per channel can positively impact performance. Other sources say single ranked memory is faster. There doesn't seem to be a lot of information out there on this that is well done where all factors are controlled. This particular piece did not factor in using dual rank DIMMS in a 2x8 or dual ranked in 4x4 configuration, ensuring all 4 configs are controlled for speed. That is also important information. Would a 2x8 dual ranked be slower or faster than 4 x 4 single ranked? etc.

Seems this is worth further investigation for those that have resources available to test this.

I've always followed the best practice of running the fewest DIMMs as possible to achieve dual channel. The only time I've ever considered memory rank when buying is when upgrading dual socket servers since quad rank is more common and you are often limited by the amount of QR DIMMS you can use, when also factoring in populating for quad or hexa channel.
 
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I have always had trouble OC'ing memory past the standard JEDEC specs once you get past a two stick config. I wonder if going with two ranks of dual channel would be better than an OC past JEDEC specs.
 
The effect on my 7700K@5GHz seems minimal with 2x8 single rank vs 4x8 single rank.
But systems with more cores would be more constrained by memory bandwidth so could see larger gains.

I doubt you would see any difference with 2x8 dual vs 4x8 single other than possible OC limitations on daisychain preferring two sticks vs T-top MB preferring 4 sticks.

Haven't looked at those videos yet but all past tests I have seen didn't take into account the changes in sub timings between different kits.
 
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This is such a complicated subject due to the fact RAM is more about page hits and it ability to operate at the frequencies for I/O, data buses, and shit to provide the page. What to install, and how to install is the key important factor. Rank will always provide a better performance due to interleaving of the banks and controllers. To configure for-your-set up is very caveat emptor. Here is a Tom's article (and there are many other if you look around) about ranks: https://www.tomshardware.com/reviews/amd-ryzen-3000-best-memory-timings,6310-2.html.

That better is a bit more, but not tremendous. But when you look at cost, stability, functionality I always go dual rank with dual and quad channel. ~5% for no extra cost instead of overclocking, dunno but that is my MO. Installing in all bank depends on the topology and many other things. So, as usual, when it comes to shit like this caveat emptor
 
I have had two 16GB kits (4x4GB and 2x2GB) and two 32GB (4x8 and 2x16) and in both cases the 4 DIMM setups overclocked better than when using the two higher capacity DIMMs. Completely subjective experience of course, but I found it surprising. Of course there's more to consider like platform, chipset, memory controller, etc.

Anyone claiming to have absolute knowledge here is probably just looking for controversy clicks.
 
I'm using Corsair LPX 4x4GB 3000MHz C15 in a Maximus VIII Hero board.
With 2 lower spec motherboards the best I got was 2500MHz almost fully stable.
With this higher spec board they clock to 3733MHz C17 @ 1.44V, not bad for D die.
 
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