[SOLVED] Two wired PCs - one has lag, one doesn't

[Fortnite_mom]

I hope someone can help - apologies in advance for being long.

I'm losing my mind trying to find the needle in the haystack that is causing lag on only one of my boys' gaming PCs. They both play Fortnite on PCs connected via Ethernet cables to the router. I've followed directions to optimize both PCs for best Fortnite settings from here: https://www.gamingscan.com/best-settings-fortnite/, however, one PC experiences build delay/lag and the other one plays fantastic. Naturally you would think it's the PC, but I'm going to list hopefully all the specs needed to show that it shouldn't be the PC.

Computer #1, that runs Fortnite fine with no lag or delays and Ping always under 30, is a 6-and-a-half-year old custom built PC that connects the internal LAN to the router via a short Cat5 cable.
CPU: Intel Core i7-3820 Sandy Bridge-E 3.6GHz 10MB Cache Quad-Core
Motherboard: ASUS Sabertooth X79 (Intel X79, 3xPCI-E, 8xSATA, 8xDDR3)
Power Supply: 850watt Corsair CMPSU-850TX V2 80 PLUS CERTIFIED
OS: Microsoft Windows 10 Professional 64bit
Graphic Card: Nvidia 2GB GeForce GTX 660Ti GDDR5 PCI-E Dual-DVI/HDMI
Ram: 32GB (8GBx4) Corsair Vengeance 12800 DDR3 1600Mhz

Computer #2, a pre-built Cyberpower PC, that consistently experiences build delay and renders it unplayable in competitive solo matches, suffers Ping that goes from 15-50, and was just purchased this past August. It experiences lag/build delay with the internal LAN connected to the router via the same Cat5 Ethernet PC#1 is connected to, with a brand new, 25 ft. Cat6 cable that runs through the floor to the basement, and via a brand new 50ft. Cat7 cable purchased to check and see if the Cat6 cable wasn't working.
CPU: Intel Core i5-9400F 2. 9GHz 6-Core
Motherboard: ASUS Prime B360M-A
Power Supply: I can't see the brand, I'm guessing 500watt
OS: Microsoft Windows 10 Home 64bit
Graphic Card: NVIDIA GeForce GTX 1660 Ti 6GB Video Card
Ram: 8GB Ballistix Sport Red
(Here is the actual link to the PC:
https://www.amazon.com/gp/product/B07N9KWYSY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 )

ISP: Spectrum - only option we have for service. Speedtests on both PCs consistently show Ping 20-25, download 110 Mbps range, and upload 10 Mbps range. Spectrum also only offers one bandwidth speed.

Router: ASUS TM-AC1900
Modem: Arris TM1602

We have many wireless devices, however, they are not all always turned on and being used. The ones that are pretty much always on are: 4 i-Phones, 2 laptops, and 2 Alexas. We have other devices, but I'm assuming that unless they are turned on they aren't pulling bandwidth so I won't list them. We don't watch Netflix via WiFi because that interferes with the Ping on the PCs.

PC#2 even has problems when PC#1 is shut down. According to everything I've read, the specs should be more than enough to handle Fortnite. Both keep the View Distance setting at Epic, but every other setting is set to low or off, as per all the Fortnite setting recommendations.

Originally we had the new PC#2 connected wirelessly one level down in the basement. Then we drilled a hole through the floor to connect it via Ethernet with the 25 ft. Cat6 cable... still lag. Then I took PC#1 and moved it downstairs, and gosh darn it PC#1 had the same lag/build delay issues! So of course I thought we must have damaged the cable running it through the floor. I bought a 50ft. Cat7 cable and ran it downstairs (not through the floor)... same lag issues. I moved PC#2 upstairs, connected it with the Cat5 cable PC#1 uses, and still lag!

It shouldn't be the PC. What am I missing??? Can someone please help?

 

[rgd1101]

make and model of the psu?
latest bios?

 

[kanewolf]

That 8GB RAM might be your problem. Is that one or two DIMMs?

 

[Fortnite_mom]

make and model of the psu?
latest bios?

Thank you for the reply.
I cannot see the PSU. It's underneath a metal shelf inside the tower. Tomorrow I will call the Cyberpower number and try to find out. Also, the PC is new and I've never updated the BIOS. We've only had it a month, so I can't imagine it be super out-of-date.

 

[Fortnite_mom]

That 8GB RAM might be your problem. Is that one or two DIMMs?

Thank you too. I've thought about the RAM, however, minimum requirements Fortnite are only 4GB. Regardless, it is one DIMM. I have thought about figuring out how to install a second one and order another one.
I always thought RAM was more so you could have multiple programs open, and since he only has Fortnite open, and it's not supposed to be super intensive with graphics, I assumed 8GB would be okay. Maybe that should be my next step. Thanks

 

[kanewolf]

Thank you too. I've thought about the RAM, however, minimum requirements Fortnite are only 4GB. Regardless, it is one DIMM. I have thought about figuring out how to install a second one and order another one.
I always thought RAM was more so you could have multiple programs open, and since he only has Fortnite open, and it's not supposed to be super intensive with graphics, I assumed 8GB would be okay. Maybe that should be my next step. Thanks

The CPU has a predefined number of memory interfaces, in the case of an Intel i5-9xxx series CPU it is two. To get maximum performance from that CPU you want two DIMMs from a matched set. A single DIMM causes the CPU to wait for data from main memory. That can cause lagging.
The total number of GB is related to how many simultaneous programs you can have in memory. But number of DIMMs is for performance.

 

[Fortnite_mom]

The CPU has a predefined number of memory interfaces, in the case of an Intel i5-9xxx series CPU it is two. To get maximum performance from that CPU you want two DIMMs from a matched set. A single DIMM causes the CPU to wait for data from main memory. That can cause lagging.
The total number of GB is related to how many simultaneous programs you can have in memory. But number of DIMMs is for performance.

I loved how you explained this... number of DIMMS is for performance. Thank you!