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Corsair 2 x 24GB DDR5-7000 Memory Linux Performance

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  • willmore
    replied
    Originally posted by Classical View Post

    Phoronix's test is quite misleading. In the vast majority of situations there is little difference between DDR4 @ 3600 and DDR5 @ 6000

    Here's an example from reality:​ https://www.thefpsreview.com/2022/04...oard-review/7/

    From a performance perspective, we compared the $320, midrange BIOSTAR Racing Z690 GTA with DDR4 memory against a $1,100 top tier DDR5 motherboard and DDR5 6000MHz RAM. Despite the massive cost difference, the BIOSTAR Racing Z690 GTA did extremely well coming within 1-3% of the much more expensive test platform. In some cases, the BIOSTAR Racing Z690 GTA achieved even better results than the aforementioned price behemoth of a test system.
    The best thing I can say for that review was that it was trash. They really need to learn how to document system configurations better. We have no idea what the memory timings were set to and they used different CPUs and thermal solutions and then pretend the differences were due to the memory? This reads like "my first PC review". Also, their web site it horrible, how to people put up with that formatting?

    They run very few benchmarks and those they do run are poorly documented--they don't report program version nor setup. They don't say what clocks they're running the various memory setups at. From what I can tell, they're using extremely low latency DDR4--3600CL16 vs DDR5-6000CL36. The DDR5 is reasonable if a little high, but the DDR4 is super low!

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  • Classical
    replied
    Originally posted by bug77 View Post
    Whoaa, at those prices I am tempted to move my 12600k to DDR5. If I can find a decent mobo (I'm picky about those) that won't break the bank.
    Phoronix's test is quite misleading. In the vast majority of situations there is little difference between DDR4 @ 3600 and DDR5 @ 6000

    Here's an example from reality:​ https://www.thefpsreview.com/2022/04...oard-review/7/

    From a performance perspective, we compared the $320, midrange BIOSTAR Racing Z690 GTA with DDR4 memory against a $1,100 top tier DDR5 motherboard and DDR5 6000MHz RAM. Despite the massive cost difference, the BIOSTAR Racing Z690 GTA did extremely well coming within 1-3% of the much more expensive test platform. In some cases, the BIOSTAR Racing Z690 GTA achieved even better results than the aforementioned price behemoth of a test system.

    Leave a comment:


  • torsionbar28
    replied
    Originally posted by SteamPunker View Post
    UPDATE: I searched a bit on-line for the answer, and apparently, this is allowed by the DDR5 specification, and the "whole power of two" thing was more of a traditional convention in the PC industry, with other hardware such as smartphones already having done away with it for some time. (Indeed, some phones even shipped with 3GB of RAM, which is not only not a whole power of 2, but an odd number, which feels even dirtier. ) Source: https://www.anandtech.com/show/17117...b-ddr5-modules
    It sounds like you're confusing total system memory with module size. Total system memory has never been tied to power-of-two, with "odd" sizes actually quite common place. 3 GB of RAM is nothing new, and not limited to phones. Most all the intel products from around 12 years ago had triple-channel memory, so total system RAM of 3 GB or 6 GB or 12 GB was the norm. At the time, it was only AMD systems that had 2 or 4 or 8 GB of memory. Having three sticks of memory was common in the Super Socket-7 days as well, with 384 MB, 768 MB and 1.5 GB being common memory sizes. All of these "odd" sums however were composed of base-two modules. e.g. 3x1G=3G. 3x512M=1.5G. and so forth.

    What is unique here in the DDR5 era as highlighted by this article, is the advent of non-base-two sized modules. This is unrelated to total system memory size, phones with 3GB are not relevant to this discussion. Does that make sense?
    Last edited by torsionbar28; 24 April 2023, 12:29 AM.

    Leave a comment:


  • yump
    replied
    Originally posted by piotrj3 View Post
    Motherboard manufacturers should really make more motherboards for ddr5 that have 2 slots, 2 slots means shorter traces, less traces, lower costs and better singnal integrity. Heck possibly it could even allow to have less layers in motherboard and that would even more bring costs down.
    ASRock's cheapest B650 is exactly that.

    Leave a comment:


  • yump
    replied
    Originally posted by avis View Post
    Strangely mobile APUs support up to LPDDR5x-7500.
    Nothing strange about it. DDR on desktop has 2 sockets in path. LPDDR on mobile has 0.

    Leave a comment:


  • piotrj3
    replied
    Originally posted by pieman View Post
    and people also forget infinity fabric is tied to dram speed as well. so its always in a 1:1 ratio. that means memory is also limited by infinity fabric. you can decouple it but you'll get a pretty big performance hit. 6000mhz is pretty much the max because of infinity fabric. buildzoid of actual hardcore overclocking was able to get higher speeds by decoupling but the performance loss isn't worth it. the memory controller on the i/o die still doesn't allow for speeds high enough to make up for the performance loss. and even with zen4 chips that can do 6200-6400, many of them are not fully stable. random crashes / system freezes can happen out of the blue. zen4 really isn't stable above 6000.

    intel on the other hand as noted by michaels own review can do 7000 fairly easily with single rank kits. others have hit 8000 but most wont. and intel's, like zen4, really gets bad when dealing with four modules to occupy all four dim slots. or dual rank, high capacity kits. 6000mhz single rank 32gb kits will work fine. but dual rank 64gb kits? even if its just two 32gb modules, at dual rank per module its really stressful on the controller. with my 13700kf i went with a 5200mhz kit because it was one of the very few 64gb kits on my motherboards QVL for 64gb and i didn't want to deal with any headaches.
    It is a bit more complicated. But generally speaking dual rank shouldn't affect that much max speeds comparing to single rank. Problem is driving 4 seperate traces for 4 seperate sticks is what really hurts signal integrity and prevents sensible overclocking. Also IF isn't always die to DRAM speed, it is tied up to certain max frequency and if you cross it, it becomes decoupled and hurts performance/latency. IF on zen 4 clocks max to 3GHz, what considering we use double rate RAM means max 6000MHz on ddr5 kits so even if you could go beyond 6000MHz it would hurt you not help you.

    Motherboard manufacturers should really make more motherboards for ddr5 that have 2 slots, 2 slots means shorter traces, less traces, lower costs and better singnal integrity. Heck possibly it could even allow to have less layers in motherboard and that would even more bring costs down.

    Leave a comment:


  • pieman
    replied
    Originally posted by Brane215 View Post

    Actually, it's pretty much the top that you can count on. Almost everything above that is a lottery.
    Article that you mention talks about _their_ chip and other "good samples".
    and people also forget infinity fabric is tied to dram speed as well. so its always in a 1:1 ratio. that means memory is also limited by infinity fabric. you can decouple it but you'll get a pretty big performance hit. 6000mhz is pretty much the max because of infinity fabric. buildzoid of actual hardcore overclocking was able to get higher speeds by decoupling but the performance loss isn't worth it. the memory controller on the i/o die still doesn't allow for speeds high enough to make up for the performance loss. and even with zen4 chips that can do 6200-6400, many of them are not fully stable. random crashes / system freezes can happen out of the blue. zen4 really isn't stable above 6000.

    intel on the other hand as noted by michaels own review can do 7000 fairly easily with single rank kits. others have hit 8000 but most wont. and intel's, like zen4, really gets bad when dealing with four modules to occupy all four dim slots. or dual rank, high capacity kits. 6000mhz single rank 32gb kits will work fine. but dual rank 64gb kits? even if its just two 32gb modules, at dual rank per module its really stressful on the controller. with my 13700kf i went with a 5200mhz kit because it was one of the very few 64gb kits on my motherboards QVL for 64gb and i didn't want to deal with any headaches.
    Last edited by pieman; 22 April 2023, 09:11 PM.

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  • qarium
    replied
    Originally posted by avis View Post
    Desktop Zen 4 CPUs don't support/run with DDR5 faster than 6000MHz. Just so you knew. And if you have four DIMM slots populated you're f*cked: only 3600MHz for you.
    Strangely mobile APUs support up to LPDDR5x-7500.
    what you really want is this:
    " AMD and JEDEC Develop DDR5 MRDIMMs With Speeds Up To 17,600 MT/s"

    Leave a comment:


  • SteamPunker
    replied
    I haven't been following the latest developments in PC hardware as closely as I once did. But I'm used to memory modules always having a capacity that is a whole power of 2. So after 16GB modules, I thought we'd go straight to 32GB modules. 24GB modules, that just feels weird.

    Maybe I'm just being autistic about it, I don't know. How long has this been a thing?

    UPDATE: I searched a bit on-line for the answer, and apparently, this is allowed by the DDR5 specification, and the "whole power of two" thing was more of a traditional convention in the PC industry, with other hardware such as smartphones already having done away with it for some time. (Indeed, some phones even shipped with 3GB of RAM, which is not only not a whole power of 2, but an odd number, which feels even dirtier. ) Source: https://www.anandtech.com/show/17117...b-ddr5-modules
    Last edited by SteamPunker; 22 April 2023, 09:50 AM.

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  • Brane215
    replied
    Originally posted by Luke_Wolf View Post
    6000 isn't the max, it's just the recommended RAM speed based on AMD's findings about price/performance. Per various benchmarking sites like Tom's Hardware https://www.tomshardware.com/reviews...000-c34-review 6400-6600 is as far as you can really go though, so yeah 7000 MHz RAM is useless in a Zen 4.
    Actually, it's pretty much the top that you can count on. Almost everything above that is a lottery.
    Article that you mention talks about _their_ chip and other "good samples".

    Leave a comment:

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