I have a PC with an AMD built RX580, X370 chipset and Ryzen 1700X cpu. I notice that the GPU is connecting at PCIe X8 and not X16. When I run GPU-Z, it shows this; PCIe x16 3.0 @ x8 1.1. If I load the GPU with FurMark, the GPU-Z dsplays @ x8 3.0. I have 4 PCI expansion slots, only 1 occupied with the RX580. I have an M.2 SSD sata connected. I need to make sure the motherboard is operating properly as I only have a few more days to return it if it is defective. It is a Dell Inspiron 5675.
AMD Radeon GPU shows connected at PCIe x8
- Thread starter krking111
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Frag Maniac
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It's likely using x8 bandwidth due to the proprietary MB, which may not have as good Pci-Ex lane support as others, especially with an SSD installed. The new high speed M.2 drives take up 4 Pci-Ex lanes.
It's pretty much a non issue at Pci-Ex gen 3 bandwidth though.
Here's an FPS test on Pci-Ex 3.0 slots comparing x8 vs x16 on a GTX 1080, which is roughly 50% more powerful than a RX 580. Of the 5 games tested, 3 had identical Ave FPS, and the other two were within 1 FPS of each other.
[video="https://www.youtube.com/watch?v=XJuj16gRoBI"][/video]
Bottom line, this is not the kind of thing that's worth removing the SSD to solve, as it's not really a problem and there's no guarantee removing it even would yield x16 for the GPU given the proprietary MB (though I'm guessing it would).
Now if Dell is advertising the system as having a Pci-Ex x16 slot, it likely does, but it's probably cut to x8 when you opt for the SSD drive. Keep the rig, keep the M.2, and enjoy it. Such minute differences in performance aren't even perceptible to the naked eye, except in bench tests, and only via the numbers, not what happens onscreen.
It's pretty much a non issue at Pci-Ex gen 3 bandwidth though.
Here's an FPS test on Pci-Ex 3.0 slots comparing x8 vs x16 on a GTX 1080, which is roughly 50% more powerful than a RX 580. Of the 5 games tested, 3 had identical Ave FPS, and the other two were within 1 FPS of each other.
[video="https://www.youtube.com/watch?v=XJuj16gRoBI"][/video]
Bottom line, this is not the kind of thing that's worth removing the SSD to solve, as it's not really a problem and there's no guarantee removing it even would yield x16 for the GPU given the proprietary MB (though I'm guessing it would).
Now if Dell is advertising the system as having a Pci-Ex x16 slot, it likely does, but it's probably cut to x8 when you opt for the SSD drive. Keep the rig, keep the M.2, and enjoy it. Such minute differences in performance aren't even perceptible to the naked eye, except in bench tests, and only via the numbers, not what happens onscreen.
Thanks for the reply. The PCI connection should be at x16 if the motherboard is working correctly, right? Dell advertises this motherboard as having 2 PCIe 3.0 x16 slots. Also, the SSD is on the SATA connection, which shouldn't interfere with the PCI bus for the CPU, unless there is a defect. Another person with the same issue changed to the other PCI slot and still at x8. I wonder if I should return the PC. My return window closes soon. Dell says their tech support is working on the issue but no result in over 2 weeks.
Frag Maniac
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First off, odd that a M.2 drive would not be connected straight to the M.2 slot on the MB.
Second, before even posting my last response I searched for info about the MB on that model of Dell. The only pic I found of the MB showed it having one full size Pci-Ex slot, and 3 small ones. They may have revised it since though.
Third, just because a MB is speced as having two x16 Pci-Ex slots doesn't mean they'll always operate at that speed. It generally depends on how many Pci-Ex lanes are taken up by other devices. Those lanes have to be allocated somehow. It's certainly not the PSU doing it.
Anyways, I still feel it's a non issue, even if Dell comes out with a BIOS update for the MB yielding x16 on the GPU slot, you won't notice it in actual gaming. The only time you'll notice it is when monitoring bandwidth usage, or in bench numbers like the one I showed you.
If you got a good deal on the PC, I'd keep it, especially if the only return option is to pay to ship it back, which is expensive.
Second, before even posting my last response I searched for info about the MB on that model of Dell. The only pic I found of the MB showed it having one full size Pci-Ex slot, and 3 small ones. They may have revised it since though.
Third, just because a MB is speced as having two x16 Pci-Ex slots doesn't mean they'll always operate at that speed. It generally depends on how many Pci-Ex lanes are taken up by other devices. Those lanes have to be allocated somehow. It's certainly not the PSU doing it.
Anyways, I still feel it's a non issue, even if Dell comes out with a BIOS update for the MB yielding x16 on the GPU slot, you won't notice it in actual gaming. The only time you'll notice it is when monitoring bandwidth usage, or in bench numbers like the one I showed you.
If you got a good deal on the PC, I'd keep it, especially if the only return option is to pay to ship it back, which is expensive.
Well, the motherboard on this system has 2 full length PCI slots and 2 short PCI slots. There are 2 available for the system, depending if it is a Ryzen CPU or an APU. The M.2 SSD is in a separate M.2 slot on the motherboard. I heard back from Dell support today and they told me this computer would run at PCIe 3.0 x8 max. I guess they went cheap on the motherboard. Thanks for the replies.
Frag Maniac
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Yeah, that's where M.2 drives are typically installed, and the new high speed ones DO cancel out 4 of your previously usable Pci-ex lanes once they're installed due to the bandwidth they require. You may have thought the way I worded it previously I meant they are plugged into Pci-ex slots, but no, they just rob you of some of your Pci-ex lanes.
When you spoke to Dell last you should have asked him if the GPU slot would output at x16 without the M.2 drive installed, just to clarify why they were saying the MB has x16 slots. Him saying the computer is limited to x8, isn't necessarily the same as the MB being limited to that. He could have meant with that configuration, meaning with the M.2 drive.
You could test this yourself if you have a HDD to install Windows on. Just remove the M.2, install Windows on the HDD (using a small 30GB partition just for the OS or you'll lose all data on that drive when you go back to the way it was), then boot into the OS on the HDD and check your Pci-ex bandwidth again.
IMO that would only be to satisfy your curiosity. The way I look at it, you have the benefit of a very fast boot drive, and the only tradeoff is a loss of like half a frame at 60 FPS when gaming, which you'll never in a million years notice.
Don't blame Dell, this is how big manufacturers of OEM PCs keep their prices low, and if it weren't for your looking at specs and monitoring your Pci-ex bandwidth, you'd have never even known it anyway.
Hell, even with my 1080 Ti rig I don't have a boot drive as fast as an M.2. In fact my SSD is only capable of about 350 Mb/s write speed, but only doing about 245 at best due to the crappy SATA 3 controller my MB has.
The only real bad thing I have to say about OEM builds like Dell, is they use very proprietary parts, so they're hard to upgrade, and you get better bang for buck building your own. They do suffice for those whom can't or don't have time to build though, so the convenience is worth the price for many.
Frag Maniac
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