3 pcs on a 10gb switch one has very slow writes

Networking Networking Hardware
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I have 3 pcs hooked up through a mikrotik sfp+ switch pc A has a 10gb sfp+ card pc B has a 10gb sfp+ card pc C has a 5gb aquantia nic with a sfp+ to rj45 in the switch pc a b and c can transfer to a or b with much greater than gigabit performance no issue however pc C when having files transfered to it from pc a or b has very slow write speed around 10 to 20 mbps (2 nvme drives in raid 0 not a drive bottleneck) im at a loss

Sorry for the run on sentence also i am very very new to networking stuff as a headsup

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Windows or Linux?

Can you try iperf3 (command line tool that tests tcp/udp transfer speeds in one, other, both directions ;; use it to test just network speeds without involving any filesharing software or hardware)

Is this the CRS305 or some other switch? Are you sure you’re running on the same MTU on all ports and not asking the Mikrotik switch to firewall or route stuff between ports? What RJ45 transceiver are you using?

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100 % run that first as a test. and if results are bad as well do direct computer to computer test to verify nics are good and to identify is switch is the issue or not

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I ran iperf on all 3 machines using each as a server and a client they all were able to get at or over 2gbs. This is the adapter im using https://www.amazon.com/gp/product/B01M5LIUK5/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Yes it is the crs305 im having a very hard time getting into the switch software as i have the microtik switch plugged into a unifi 24 port switch

The device that starts with 48 is the mikrotik switch and roshi mutaito and beerus are the pcs connected to it if any of this helps.

unifi setup
unifi setup1256Ă—1292 186 KB

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what size files are you moving, and what file systems

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all are windows machines and its large mp4s mkvs and its ntfs

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Make sure you check the statistics on the NIC ports and switch ports. A large number of packet errors that are constantly increasing would be a bad sign. Sometimes iperf can show good numbers even while other TCP connections get slowed down by retransmit errors.

Also make sure the NIC and switch port negotiated 5 Gbps and not 10 or something else.

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Please see “quick guide” for this model on mikrotik website, specifically section on factory reset and on boot process and how to change to swos. As per the quick guide, start by downloading Mikrotik Winbox configuration software, and then change the crs305 to SwOS which is the simpler version of the OS that you can control through the webui, and will probably find easier to use.

Iperf3 between A-B should yield around 9.2Gbps or so assuming everything was configured correctly. Simply “bigger than 2Gbps” is indicative of some issue.

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Ok will do that right when i get home and i have seen as high as 7gbs during transfers of actual files so i thought the iperf was a little low as well. Thanks for the help.

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iperf lies and can’t rely on it in terms of throughput, in my experience it can lie even up to 200mbps.

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The weird part about all this is the machine that has the problem of receiving files very slowly can transfer at the full 5gbs(only has a 5gb nic) to both the other computers no problem it just receives files very slowly.

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So i managed to finally get into the switch when it was in router os changed it to switch os and now i cannot log back into it im being big dumb somewhere :upside_down_face:

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Got the dream machine to give the switch an ip so i can log into it i cannot find any issues within the switch settings. I purchased a new sfp+ to rj45 and a new cable that wasnt it. I have a 10gb sfp+ card coming in the mail i will try that on the pc with the issue and let yall know what happens then.

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So i bought that sfp+ card threw it in 10gb no issue.
That’s my motherboard i seen people say those switches with 5gb worked no issue I’m very surprised that turned out to be the problem.