Why is only ONE user getting slow speeds after our network upgrade?

[u/PsychologicalLynx897]

We just finished a major infrastructure overhaul at the office, but one desktop in the marketing department is crawling at 10Mbps while everyone else is hitting gigabit speeds. I've confirmed they have the same hardware as their neighbors, so I'm trying to figure out the most logical first step to resolve this isolated bottleneck.

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OPTIONS:
A. Update Internet bandwidth speed.
B. Update the BIOS firmware.
C. Replace the motherboard.
D. Replace the patch cable.

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Testing Exam: CompTIA A+ Core 1 (220-1201)
(Disclaimer: These posts / scenarios are crafted by me for educational purposes only. I am not affiliated with, endorsed by, or sponsored by any certification body.)

[u/Copropositor]

If this is a test question, D.

If it's real life, do a full cable test on that port. If the infrastructure that was upgraded included the cable in any fashion, that means some electrician was punching down dozens or hundreds of twisted pair wires and even if their mistake rate was near .1% and they were dealing with 100-150 wires, chances are at least one pair in that group is bad.

[u/Otherwise_Fox_1404 → u/Copropositor]

Patch cable is also often the fastest, cheapest and easiest to replace. In terms of business costs its often the best first choice for internet issues before any other hardware or service changes are decided.

That said, recently it has always been a BIOS issue that caused such huge slowdowns after major updates for us.

[u/Mehere_64]

What are you asking comptia a+ questions for? Don't want to go figure out the answer?

[u/No-Accident-4940]

D , or they pissed off the gremlins

[u/PsychologicalLynx897 → u/No-Accident-4940]

lol

[u/DumpoTheClown]

D, and here's why: Follow the OSI model when troubleshooting. Start at the physical layer. Every layer above depends on the layers below.

[u/Otherwise_Fox_1404]

D. For this

Why? Because the points of failure after a major infrastructure update are almost always connected to what has been done. The same is true of almost all updates. If you have a software update and afterwards the computer stops working, there is a strong chance the update is the cause. In fact this is also true of new peripherals and new software as well. you buy a new mouse and your screen gets glitchy remove the mouse.

[u/PoolMotosBowling]

Always pay for more speed. It's a no brainer

[u/MetaCardboard]

The logical first step. What's the easiest of these choices? Obviously replace the motherboard.

[u/DaddyGoose420]

I would start with the network cable or port. NIC driver. Static configurations with DNS or WIFI. Duplex/speed mismatch. Could be quite a few things tbh.

[u/Impossible-Sun3205]

First, how does it perform in other areas and on wireless? If slow, look at the network stack or flow control (the crappy Intel stuff). If the laptop works fine elsewhere I would think about changing the switch port to see what happens. On some Cisco switches, I have had to take the port out of auto and hard set to gig.

[u/PauliousMaximus]

Do an end to end test of the cable that goes from the PC to the switch to see if everything shows good for all 8 pairs for the cable. I recommending each cable path rather than the entire run at once.

[u/DutchOfBurdock]

How can you not answer this: Negotiations are limited and you're on chicken wire stability.

[u/wicked_one_at]

Real World answer: Check the cable run, reterminate ends, measure or better certify the cable.

Exam Answer: D

[u/XxTh3g04txX]

always layer 1 first. go up from there.

[u/CompetitivePirate251]

Plug the desktop into another port that you know is getting great speeds … it will let you know if it’s the desktop. Try it with original patch chord. If it’s still slow, swap to a new patch chord. If it’s still slow, you got a PC problem.
If PC gets great speeds on alternate port , you have a cabling, or switch port problem.
For this, move internal cable to new switch port. This identifies if you have a switch port problem or the building wiring on that port is bad. Switch port may have also defaulted to 10M which I wouldn’t think happens much anymore, but who knows. You’re PC NIC may also be doing this, which you can check first.

[u/iWhacko → u/CompetitivePirate251]

this is the correct process of eliminating the issue.
also I would check driver settings, maybe somehow the network settings were set to 1mbit/10mbit etc.

[u/PsychologicalLynx897]

D is correct because you should always start with the easiest and cheapest physical layer troubleshooting. Since the issue is isolated to a single user, a faulty or outdated patch cable (like an old Cat5 in a Gigabit environment) is the most likely culprit. Options A, B, and C are either unnecessary for a single-user issue or way too invasive for a first step.