May 17, 20215 yr Questions about speed when card is in a Physical x16 but operates at x4? Unraid system, now have 2 Parity drives and 5 data drives. I notice it is not as fast as I thought it would be, maybe after adding 2nd Parity. Seem to max out per drive at 40MB/s when writing you will also see it reading at the same time on the same drive, and it is also reading and writing the 2 parity drives. PCIe 2.0 x16 1660Super GPU mining Ethash in VM Win10 PCIe 2.0 x16 but operates at x4 9211-8i card ASUSTeK COMPUTER INC. M5A97 R2.0 AMD FX-8370 Eight-Core Video boot device is not the 1660Super but a PCI old video card because of Unraid. Is the x4 operation of the 9211-8i the bottle neck? Motherboard? Yes know it is old but works. I might be able to swap the 1660Super to the x4 slot & put the 9211-8i in the 16x slot, would this make any difference.
May 17, 20215 yr Author Just realized that the slower read speeds are from a VM on Unraid box running Win10 reading an Unraid share, so it is over the network. So I will have to look for a way for the VM to read/write to the Unraid share directly without network. Can I mount the Unraid share directly from the Win10 VM running on Unraid. /mnt/user/name_of_share Edit: I remember seeing Parity checks reading drives at 135MB/s each and maybe slower as it gets near the end. Edited May 17, 20215 yr by Paul_Ber
May 17, 20215 yr If you're just using your GPU for mining, four PCIe lanes is more than enough. Motherboards designed specifically for mining have only single lane connections. Regarding disk controller throughput, this article might be of interest, in particular this section: Quote Dell H310 PCIe gen2 x8 (4000MB/s) - 6w – LSI 2008 chipset, results should be the same as for an LSI 9211-8i and other similar controllers 4 x 455MB/s 6 x 377.5MB/s 8 x 320MB/s (190MB/s*, 185MB/s**) *on PCIe gen2 x4 (2000MB/s) **on PCIe gen1 x8 (2000MB/s) where eight disks connected to a controller in a gen2 x4 slot get about 190 MB/s each during a parity check (ie. when all are active at the same time).
May 17, 20215 yr Author 33 minutes ago, John_M said: If you're just using your GPU for mining, four PCIe lanes is more than enough. Motherboards designed specifically for mining have only single lane connections. Regarding disk controller throughput, this article might be of interest, in particular this section: where eight disks connected to a controller in a gen2 x4 slot get about 190 MB/s each during a parity check (ie. when all are active at the same time). Kept VM running with 1660Super mining. On VM stopped Burst mining for this test. Top 2 lines are 2 Parity Bottom line is total. Tried with GPU & Burst mining stopped and get about same results but starts at 145MB/s(each HDD) from the PCIe 2.0 x16 operating at x4 slot with 9211-8i HBA card for those 7 drives. I guess I could also try the speed test on individual drives to see if worth swapping the 2 cards. It would be quite a chore to swap the 2 cards, would have to undo all the Nvidia pass thru and then readd because it would up in different slot. Edited May 17, 20215 yr by Paul_Ber
May 17, 20215 yr 11 minutes ago, Paul_Ber said: I guess I could also try the speed test on individual drives. There's a Docker container for doing that. You'll see that typical hard disks start off fast at the outer cyclinders and slow down considerably as they reach the inner cylinders. I have no idea what disks you have so I don't know if you're expecting faster than 140 MB/s, but it should be fairly clear that the PCIe connection is not the bottleneck. Unless both slots are connected via the chipset, they don't share bandwidth to the CPU and mining doesn't involve moving much data anyway - it's all about number crunching.
May 17, 20215 yr Author Ok I tried taking out the GPU for now. Moved the 9211-8i to the PCIe 2.0 x16 slot. It seems to be stuck in x4 mode per that Docker Disk Speed. Will put it back how I had it for now. Even if it was working in x8 mode in the x16 I don't have room for the GPU in the x4 slot because I would need a PCI riser cable for an old VGA card plugged into a PCI slot. Edit: Looking Unraid log I see this, "16.000 Gb/s available PCIe bandwidth, limited by 5.0 GT/s PCIe x4 link at 0000:00:02.0 (capable of 32.000 Gb/s with 5.0 GT/s PCIe x8 link)" Edited May 17, 20215 yr by Paul_Ber
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