[SOLVED] Questions about PCIe 4.0, M.2's, CPU and RAM

emitfudd

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It looks like the Asus Crosshair Dark Hero motherboard will run both of it's M.2 slots in 4.0. The Maximus XIII Hero has a total of 4 M.2 slots but only 2 of them run at 4.0 and the other 2 at 3.0. Looking for clarification on a few things. If I am reading the specs correctly, using 2 M.2 slots on either board will cause the PCIE 16x slot for the GPU to run at 8X? Is this correct and does it matter? I have a 3080 GPU. Will running it at 8x hinder performance in any way? If so, is there any way to utilize 2 M.2 slots and keep the 16x speed?

I don't need a ton of storage space. I am currently running 2 500GB M.2's and occasionally have to delete an old game to free up some space. Is it better to utilize one M.2 for the OS and programs and the other M.2 for games?

I know one of these motherboards is for AMD and the other is for Intel. I am warming up to the idea of going with a Ryzen 5900x. I am also considering the 11900K. After watching many youtube comparisons on the 2, it looks like the gaming performance is close enough that either will provide about the same FPS but the Ryzen does so with lower clock speed which uses less power which creates less heat. I have a 360mm AIO so would probably be ok with either.

The Maximus XIII Hero specs say it can run RAM of speeds up to 5333MHz. The Crosshair Dark Hero max RAM is 5100MHz. I don't know if I would go that high because it would be very expensive. What speed would work best with either of these boards? I am currently running 32GB of DDR4 3200 but can only get it stable at 3000. I remember reading somewhere that the Ryzen 5900x would benefit from 4 RAM sticks instead of 2. Example, 4x8GB instead of 2x16GB. Is this correct? I like the look of having 4 RAM sticks with LED's.

If anyone has any other information that would be good to know in making the AMD vs Intel decision, I'm all ears.

Specs for the build I am considering:

I am currently using a 1440P monitor with 165Hz refresh and 1ms response time and Gsync. May upgrade to a 4K at some point.

Asus Crosshair Dark Hero or Asus Maximus XIII Hero
Ryzen 5900x or Intel 11900K
MSI 3080 Gaming Z trio (already have it)
32GB of RAM. Speed and brand tbd.
Samsung 980 PRO M.2 1TB x 2 or 2TB x1
1000 W PSU brand tbd
Corsair 780T case
Thermaltake Water 3.0 Ultimate 360mm AIO
 
It looks like the Asus Crosshair Dark Hero motherboard will run both of it's M.2 slots in 4.0. The Maximus XIII Hero has a total of 4 M.2 slots but only 2 of them run at 4.0 and the other 2 at 3.0. Looking for clarification on a few things. If I am reading the specs correctly, using 2 M.2 slots on either board will cause the PCIE 16x slot for the GPU to run at 8X? Is this correct and does it matter? I have a 3080 GPU. Will running it at 8x hinder performance in any way? If so, is there any way to utilize 2 M.2 slots and keep the 16x speed?
Crosshair Dark Hero: Neither slot will take lanes from the GPU. Ryzens have four PCIe lanes dedicated for general use (which ends up being the M.2 slot) and the chipset provides PCIe 4.0 to the other M.2 slot. You will likely lose a few SATA ports if you use the secondary M.2 slot however.

Maximus XIII Hero: The primary M.2 slot has its own set of lanes. The secondary slot will take lanes from the GPU slot.

Even if the M.2 slot takes lanes meant for the GPU, the 3080 runs with almost no performance loss at PCIe 4.0 x8. See https://www.techpowerup.com/review/nvidia-geforce-rtx-3080-pci-express-scaling/27.html (PCIe 3.0 x16 is the same as PCIe 4.0 x8)

I don't need a ton of storage space. I am currently running 2 500GB M.2's and occasionally have to delete an old game to free up some space. Is it better to utilize one M.2 for the OS and programs and the other M.2 for games?
Either set up is not better than the other. It just depends on what you're willing to put up with. For instance:
  • Having one drive means all of your storage space is in a single pool, so it's more flexible. Splitting up storage means you have to keep tabs on how much space is available between the two (though you shouldn't be filling up SSDs near capacity anyway)
  • Having two drives makes it easier to reinstall Windows if you have to, since the data on the other drive isn't affected and you have another place to store any data you want to save off before doing the reinstall. And while it's not really an advantage on an pure SSD system, having two separate storage drives does mean the other drive you use to play games on won't have potential hiccups if the OS drive is being used for some reason.
I know one of these motherboards is for AMD and the other is for Intel. I am warming up to the idea of going with a Ryzen 5900x. I am also considering the 11900K. After watching many youtube comparisons on the 2, it looks like the gaming performance is close enough that either will provide about the same FPS but the Ryzen does so with lower clock speed which uses less power which creates less heat. I have a 360mm AIO so would probably be ok with either.
If you're looking for pure performance, it doesn't really matter which one you go with.

The Maximus XIII Hero specs say it can run RAM of speeds up to 5333MHz. The Crosshair Dark Hero max RAM is 5100MHz. I don't know if I would go that high because it would be very expensive. What speed would work best with either of these boards? I am currently running 32GB of DDR4 3200 but can only get it stable at 3000. I remember reading somewhere that the Ryzen 5900x would benefit from 4 RAM sticks instead of 2. Example, 4x8GB instead of 2x16GB. Is this correct? I like the look of having 4 RAM sticks with LED's.
The sweet spot is DDR4-3600 for either system. Past that, the CPUs no longer run memory options at a 1:1 rate, which causes a large latency penalty. It's enough that you basically have to get DDR4-4600 or higher to make up the difference, and it's likely going faster isn't going to increase performance all that much anyway.

As for using 4 vs 2 sticks of RAM, 4 is slightly better due to memory operation interleaving, but not enough to matter.
 
It looks like the Asus Crosshair Dark Hero motherboard will run both of it's M.2 slots in 4.0. The Maximus XIII Hero has a total of 4 M.2 slots but only 2 of them run at 4.0 and the other 2 at 3.0. Looking for clarification on a few things. If I am reading the specs correctly, using 2 M.2 slots on either board will cause the PCIE 16x slot for the GPU to run at 8X? Is this correct and does it matter? I have a 3080 GPU. Will running it at 8x hinder performance in any way? If so, is there any way to utilize 2 M.2 slots and keep the 16x speed?
Crosshair Dark Hero: Neither slot will take lanes from the GPU. Ryzens have four PCIe lanes dedicated for general use (which ends up being the M.2 slot) and the chipset provides PCIe 4.0 to the other M.2 slot. You will likely lose a few SATA ports if you use the secondary M.2 slot however.

Maximus XIII Hero: The primary M.2 slot has its own set of lanes. The secondary slot will take lanes from the GPU slot.

Even if the M.2 slot takes lanes meant for the GPU, the 3080 runs with almost no performance loss at PCIe 4.0 x8. See https://www.techpowerup.com/review/nvidia-geforce-rtx-3080-pci-express-scaling/27.html (PCIe 3.0 x16 is the same as PCIe 4.0 x8)

I don't need a ton of storage space. I am currently running 2 500GB M.2's and occasionally have to delete an old game to free up some space. Is it better to utilize one M.2 for the OS and programs and the other M.2 for games?
Either set up is not better than the other. It just depends on what you're willing to put up with. For instance:
  • Having one drive means all of your storage space is in a single pool, so it's more flexible. Splitting up storage means you have to keep tabs on how much space is available between the two (though you shouldn't be filling up SSDs near capacity anyway)
  • Having two drives makes it easier to reinstall Windows if you have to, since the data on the other drive isn't affected and you have another place to store any data you want to save off before doing the reinstall. And while it's not really an advantage on an pure SSD system, having two separate storage drives does mean the other drive you use to play games on won't have potential hiccups if the OS drive is being used for some reason.
I know one of these motherboards is for AMD and the other is for Intel. I am warming up to the idea of going with a Ryzen 5900x. I am also considering the 11900K. After watching many youtube comparisons on the 2, it looks like the gaming performance is close enough that either will provide about the same FPS but the Ryzen does so with lower clock speed which uses less power which creates less heat. I have a 360mm AIO so would probably be ok with either.
If you're looking for pure performance, it doesn't really matter which one you go with.

The Maximus XIII Hero specs say it can run RAM of speeds up to 5333MHz. The Crosshair Dark Hero max RAM is 5100MHz. I don't know if I would go that high because it would be very expensive. What speed would work best with either of these boards? I am currently running 32GB of DDR4 3200 but can only get it stable at 3000. I remember reading somewhere that the Ryzen 5900x would benefit from 4 RAM sticks instead of 2. Example, 4x8GB instead of 2x16GB. Is this correct? I like the look of having 4 RAM sticks with LED's.
The sweet spot is DDR4-3600 for either system. Past that, the CPUs no longer run memory options at a 1:1 rate, which causes a large latency penalty. It's enough that you basically have to get DDR4-4600 or higher to make up the difference, and it's likely going faster isn't going to increase performance all that much anyway.

As for using 4 vs 2 sticks of RAM, 4 is slightly better due to memory operation interleaving, but not enough to matter.
 

emitfudd

Reputable
Apr 9, 2017
225
20
4,595
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Crosshair Dark Hero: Neither slot will take lanes from the GPU. Ryzens have four PCIe lanes dedicated for general use (which ends up being the M.2 slot) and the chipset provides PCIe 4.0 to the other M.2 slot. You will likely lose a few SATA ports if you use the secondary M.2 slot however.

Maximus XIII Hero: The primary M.2 slot has its own set of lanes. The secondary slot will take lanes from the GPU slot.

Even if the M.2 slot takes lanes meant for the GPU, the 3080 runs with almost no performance loss at PCIe 4.0 x8. See https://www.techpowerup.com/review/nvidia-geforce-rtx-3080-pci-express-scaling/27.html (PCIe 3.0 x16 is the same as PCIe 4.0 x8)


Either set up is not better than the other. It just depends on what you're willing to put up with. For instance:
  • Having one drive means all of your storage space is in a single pool, so it's more flexible. Splitting up storage means you have to keep tabs on how much space is available between the two (though you shouldn't be filling up SSDs near capacity anyway)
  • Having two drives makes it easier to reinstall Windows if you have to, since the data on the other drive isn't affected and you have another place to store any data you want to save off before doing the reinstall. And while it's not really an advantage on an pure SSD system, having two separate storage drives does mean the other drive you use to play games on won't have potential hiccups if the OS drive is being used for some reason.
If you're looking for pure performance, it doesn't really matter which one you go with.


The sweet spot is DDR4-3600 for either system. Past that, the CPUs no longer run memory options at a 1:1 rate, which causes a large latency penalty. It's enough that you basically have to get DDR4-4600 or higher to make up the difference, and it's likely going faster isn't going to increase performance all that much anyway.

As for using 4 vs 2 sticks of RAM, 4 is slightly better due to memory operation interleaving, but not enough to matter.
Thank you for your answers! Very helpful. I was thinking RAM speed of 3600 would be the max that would work properly.
 

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