#1 MSI Z77 nvme pcie slots question by oldMSI 10.05.2021 20:50

I just bough a nvme ssd, I haven't tried to mod my bios yet, my motherboard is the msi z77a-g45.
The PCI_E2 and PCI_E5 are linked to the CPU and PCI_E7 to the chipset.
When I install the gpu in PCI_E2 and the ssd in PCI_E7 everything works.
When I install the gpu in PCI_E2 and the ssd in PCI_E5 the gpu gets disabled but the ssd works.
In the second scenario the GPU doesn't output video on POST and windows does not recognize it on device manager.
PCI_E5 has much higher bandwidth then PCI_E7, so I would like to use PCI_E5 for the ssd.
I have restored the BIOS defaults, and updated it to the latest version.

Is this an hardware limitation? Or am I doing something wrong, perhaps some configuration or defect?

Specs:
msi z77a-g45
3570k
gtx1060
pny cs3030 1tb
orico pcie x4 3.0 expansion card

#2 RE: MSI Z77 nvme pcie slots question by MeatWar 10.05.2021 21:07

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I suspect ur GTX1060, doesn't like PCIe 3.0 x8 instead of the default 3.0 x16.
This is wot the Z77 will do to the PCIe bus, will split the E2 & E5 to 2x PCIe x8 when it detects 2 device in these 2 slots, as it as 2 gpu's on it...

Gen3(16/0,8/8), Gen2(4)

Slots
• 2 x PCIe 3.0 x16 slots
• 1 x PCIe 2.0 x16 slot
- PCI_E7 supports up to PCIe 2.0 x4 speed
• 4 x PCIe 2.0 x1 slot


If ur motherboard setting allow it (It could be as default x4, some boards can enable this by disabling the x1 slots or some SATA ports), try to set the E7 to x4 (it may be as default x4 or x1), because ur ORICO adapter will only use PCIe 2.0 x4, no more.

#3 RE: MSI Z77 nvme pcie slots question by Erus 11.05.2021 19:27

It has to do with the pcie lanes. Older CPUs weren't coded to handle the nvme hooked up directly to the CPU. Sata and all storage drives go through the chipset then DMI link to the CPU.

The CPU will automatically throttle back the lane speed if there isn't much load on the GPU. My lane speed on the GPU throttles back to pcie 1.0 speeds when there is no demand on it. My suspicion is this is whats causing the issues with both a storage drive and GPU on the same bus.

If your running a i7-3570k it only has 16 lanes. Right away your graphics card is going to use them all. The DMI link uses X4 pcie lanes to the Z77 which it then multiplexes into 20 more lanes for the pcie slots not directly connected to the CPU. I.e.: USB, sata, audio and lan.

Xeon processors will give you 20 lanes. The most lanes a 1155 socket can support is 23 but I've never seen a processor with 23 pcie lanes. I have the e3-1280 V2 on a H77. You can find them for around $100 on eBay.

E2 and E5 are both for graphics cards. E2 if your running one card and E2+E5 if your using two graphics cards with SLI or Crossfire.

In your second scenario is the proper way to hook it up. E2 for a single graphics card and E7 for the nvme.

Pcie 2.0 will run at 500MB/s per lane. With 4 lanes it works out to 2GB/s which is faster than a lot of nvme drives on the market, but you need 4 lanes free for it to run at full speed.

#4 RE: MSI Z77 nvme pcie slots question by MeatWar 11.05.2021 19:51

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Well im sorry if my help and my words sound a bit poor to u...to my humble acknowledgment. Seems that u have it
Just to finish, no one told u that E5 is only for GPU use and its not even true.
Ur E7 slot can is a PCIe2.0 slot with a max of x4, and again unless u have a special Z77 or a special NVMe drive u wont get more of it on Intel Z77 chipset/mboard, period.

This scenario with ur current HW and an IvyBridge cpu.

Sorry i could not help u enough, Good luck.

EDIT
Private Message: I didn't post the question. I was just trying to help. I did read the manual for his motherboard though and it says e2 and E5 are for using crossfire or SLI. E2 for single graphics card.

I know English isn't your first language. No hard feeling.



My dear friend...im my 49yrs old...no one ever complained about my English (I do like to use phonetics, sry)... yes im not perfect as its not my native language.
I do apologise...as u were the starter of the post, i thought u needed some opinions on the subject, but i do appreciate if u were here to teach us and share ur knowledge. Cheers.

#5 RE: MSI Z77 nvme pcie slots question by Erus 12.05.2021 21:56

The GTX 1060 will run at X8. The issue is the combination of the X16 graphics card and X4 Nvme module. The E2 & E5 slots were meant for two identical graphics cards, or no graphics cards and just the nvme, but can't mix them up.

#6 RE: MSI Z77 nvme pcie slots question by oldMSI 19.05.2021 00:10

Thanks, I think the most plausible explanation is Erus, the 1060 works on the x4 2.0 PCI_E7.

Nowadays the majority of nvme SSDs are bottlenecked by pcie 2.0, here's mine tested by crystal disk mark and AS SSD for reference:

x4 3.0 direct to the CPU- ~3000 MBs, read latency 0.036 ms.
x4 2.0 through the chipset- ~1500 MBs, read latency 0.057 ms.

But day to day 1500 MBs is more than enough.

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