Any downside to using M.2_2 slot over M.2_1?

[Tooterfish]

Quick question. I ordered an M.2 heatsink for my Sabrent M.2 and I'm worried about airflow to both the M.2 and my GPU, being that they're so close to each other (both get very hot). I'm thinking of using the M.2_2 slot instead for my M.2 drive. The manual doesn't specifically state that I should use the M.2_1 slot first, so just curious if I will run into any issues. I'm using a Crosshair VIII Dark Hero, and specific layout is here on page 27. I have a fourth gen Ryzen.

 

[pendragon1]

if youre not chasing benchmarks it should work just fine. from the layout, i would suspect that _2 is on the chipset rather than the cpu controller so there might be a slight speed decrease, something your prob wont notice unless looking for it.

 

[Mchart]

Most chipsets will lower the speed of some other PCIE slots if you fill the second M.2 slot, and typically the second M.2 slot will be lower bandwidth regardless.

 

[vegeta535]

Depends on the chipset/MB. Like the z590 boards only get gen4 speeds in the 1st slot.

 

[pendragon1]

Most chipsets will lower the speed of some other PCIE slots if you fill the second M.2 slot, and typically the second M.2 slot will be lower bandwidth regardless.

should be full speed.

 

[Tooterfish]

Thanks for the advice. I'll quit being lazy and benchmark both slots as now I'm curious. Good to know things should run normally though.

 

[Nebulous]

On my board I noticed no difference between slot#1 and slot#2 for the M.2 drive. I preferred to use slot#1 for my M.2 drive.

 

[pendragon1]

On my board I noticed no difference between slot#1 and slot#2 for the M.2 drive. I preferred to use slot#1 for my M.2 drive.

good to know. i havent made the switch yet and wasnt sure if cpu vs chipset made a difference.

 

[Azrak]

I don't think it matters too much as long as the chipset isn't also handling a lot of PCIe data for other devices at the same time as the M2_2 slot is transferring data. The X570 link speed between the CPU and the chipset is PCIe Gen 4 x4, same as the M2_2 slot speed and the chipset handles the multiplexing for the M.2_2, SATA and USB and whatever else does I/O through it up to the CPU. It is possible for the other devices to steal some bandwidth from the M2_2 slot making it slower, but I'm guessing it would only be observed during benchmark comparisons or specific use cases.
Here are my benchmarks that I ran when I first built my system last month. Maybe a littler slower than I was expecting in some places (like read speeds), but it's good enough. The slow SATA reads I attribute to the Micron drives being more for enterprise/data center rather than consumer use, but not really sure why they cannot hit 480 MB/s+ read speed.
C: = Samsung 980 Pro 1TB (M2_1 CPU), D: = Sabrent Rocket 4 Plus 2TB (M2_2 chipset), E: and F: = Micron 1100 SATA 2TB SSDs.

 

[pendragon1]

I don't think it matters too much as long as the chipset isn't also handling a lot of PCIe data for other devices at the same time as the M2_2 slot is transferring data. The X570 link speed between the CPU and the chipset is PCIe Gen 4 x4, same as the M2_2 slot speed and the chipset handles the multiplexing for the M.2_2, SATA and USB and whatever else does I/O through it up to the CPU. It is possible for the other devices to steal some bandwidth from the M2_2 slot making it slower, but I'm guessing it would only be observed during benchmark comparisons or specific use cases.
Here are my benchmarks that I ran when I first built my system last month. Maybe a littler slower than I was expecting in some places (like read speeds), but it's good enough. The slow SATA reads I attribute to the Micron drives being more for enterprise/data center rather than consumer use, but not really sure why they cannot hit 480 MB/s+ read speed.
C: = Samsung 980 Pro 1TB (M2_1 CPU), D: = Sabrent Rocket 4 Plus 2TB (M2_2 chipset), E: and F: = Micron 1100 SATA 2TB SSDs.
View attachment 358388

thats basically what i said...

those speed pics dont help at all, they are all different *drives and on different connections. you'd need to take your rocket and test it in the two m.2 slots and compare those speeds.
*added key word that was missing...

 

[Astral Abyss]

If you're running an x570 then they should both be pcie4 capable. Only difference is the first m.2 slot has 4 dedicated lanes to the CPU. I'd be more worried about heat slowing down the drive than losing speed in the 2nd slot, so keep the beefy heatsink on it and go with the 2nd m.2.