M.2 and Sata help

[raven266]

Hello looking for help with M.2 and sata set up

 

I am building a new system i have an I7 13700k going into a MSI carbon z790 wifi mother board. I am going with a 3-storage set up. 1 M.2 NVME (pcie gen3) boot drive. 1 2TB SATA SSD for current gams. and 1 4TB SATA spinner for archive.

 

the online manual does not give information about which lanes are blocked when using different slots. IE manual says M1 anb M2 both go to CPU direct. but does not say what lanes they cut from, say if i put the M.2 boot drive into the first slot does it cut from my graphics card. or does it cut out one of the SATA to cpu. or if i put it into M2 does it cut out the second expansion slot which is covered by graphics any ways.

 

I was thinking M.2 boot into M2. my game SSD into SATA A1 so its not going through chipset but direct to cpu for speed and my spinner going to any of the chipset SATA ports, say sata 7 so they are beside each other

does anyone have thoughts if thats ok or a better set up? 

thank you

 

[Alinz]

Well, to simplify this: top slot wont affect gpu performance. There are plenty of lanes on the cpu to support both devices.

 

Your chipset also has pcie lanes, so you'll be fine just fine.

[Eigenvektor]

https://www.msi.com/Motherboard/MPG-Z790-CARBON-WIFI/Specification

Doesn't look like any lanes are cut. You have one PCIe 5.0 x16 slot and one PCIe 5.0 x4 M.2 from the CPU, one PCIe 4.0 x4 M.2 from the CPU any anything else is coming from the chipset.

[raven266]

cool ty. the last pc i built was an 8700k on an msi z390 edge board. and it mapped out every combination in the manual. for both sata and pcie m.2s and what they effect

[jlee6]

I'm actually trying to figure this out as well - MSI dropped the ball defining this clearly in the manual (both for PCIe lane splits and how there might be sharing on the chipset between M.2 slots and SATA).

The PCIe 5.0 slots that come straight off the CPU must be cut from the PCIe 5.0x16 that would otherwise by dedicated the top PCIe slot.  Raptor Lake only has 16x lanes of PCIe 5.0 from the CPU.  https://cdn.wccftech.com/wp-content/uploads/2022/09/Intel-13th-Gen-Raptor-Lake-CPUs-Raptor-Point-Z790-PCH-Details-Leak-_-Igors-Lab-_13.jpg

 

Those M.2 PCIe 5.0 lanes are definitely coming from the CPU - the Z790 chipset does not provide any PCIe 5.0.  All of this strongly suggests that this Z790 Carbon's M2_2 slot (defined in the manual as PCIe 5.0 x4, coming from the CPU) is cut from the x16 lanes, which likely drops the top PCI slot to x8 when the M2_2 slot is populated.

From a practical standpoint, this doesn't seem like a meaningful problem today... since no GPU on the market supports the full bandwidth of PCIe 5.0x16 (even the RTX 4090 is a PCIe 4.0 card).  But from a future upgrade perspective, this may become relevant.  A more immediate concern could be if any of the M.2 slots are coupled with SATA ports, which the manual doesn't seem to define clearly.....

EDIT: after writing this, I re-read the manual for the 10th time, and it confirms the PCIe 5.0 x16 cutting.  You just have to notice there's an asterisk in the Expansion Slot section on pg 15: https://download.msi.com/archive/mnu_exe/mb/MPGZ790CARBONWIFI.pdf  I swear most other manuals have made this clearer in the past (this should be reiterated on pg30 and 31).  But given there are no such asterisks on the M.2 / SATA specifications.... so maybe there's really no interaction on this board.