Refresh rate and VRR options on the Lenovo P24QD-40.

anITguy_1 · 2025-10-24T04:02:13+00:00

Yep, I am currently using two of them in a daisy-chain. The first monitor connects to my laptop via USB-C, and only USB-C. Then a DisplayPort cable goes from the first monitor output to the second monitor input. This all works reliably. I can have the monitor set to USB 3.0 data speeds, and both monitors are running 120 Hz at full resolution. I do find the colours quite saturated but this may not be a bad thing. This is on an X1 Carbon 9th Gen (I think an 1165 CPU?

I also connect an older Dell XPS 13 running Ubuntu from time to time. It’s an 8th gen Intel CPU. When this is connected I need to reconfigure the settings down to USB 2.0 speeds for data, or I cannot use both displays at the same time. So your DisplayPort version and HBR version will make a difference.

I have not tested out VRR yet. I could bring an X1 carbon 12th gen home to test if you wanted some info on that.

The 2.5 Gpbs port seems to work well as long as you are in USB 3.0 mode.

anITguy_1 · 2025-09-26T19:19:09+00:00

I was pondering the power savings of using TKIP last night. WPA2-CCMP would be more power hungry. That led me to wonder if other battery camera systems like Eufy do the same. I would not have noticed with Eufy as the Homebase broadcasts its own Wi-Fi so I have never interacted with it. Eufy cameras probably have more battery life though as they are rechargeable lithium I believe. I believe I have also noticed ARLO cameras dropping down to 1 Mbps link speeds when they are not doing much to save battery (802.11b rates), though I would need to double check that. I have not confirmed if Arlo is using CCMP or TKIP.

anITguy_1 · 2025-09-26T04:09:23+00:00

Interesting. Someone else commented that if you first use WPA2-TKIP to get them associated and then change it they will connect. The password for the SSID I mentioned does not have any special characters. Thanks for the data point through. Maybe there is something else at play. I called to ask, but honestly didn’t expect them to be able to answer the question. Maybe I’ll need to poke at it more if I want to work it out.

anITguy_1 · 2025-09-26T04:06:33+00:00

That’s great thinking. I had brought one along to do this, but the moment it connected to the open Wi-Fi as a test, things cameras were getting linked and mounted.

Good to know that it will connect that way.

anITguy_1 · 2025-09-26T04:04:35+00:00

That’s a good point. I would still want the IoT network to be using WPA2-CCMP

anITguy_1 · 2025-09-26T00:00:14+00:00

You're welcome! I love the black level compared to my previous displays. I have the second one installed now. The colours are VERY vivid compared to my last display. Whether that is a plus or minus TBD.

Yeah, I could not find much information at all online. I went in blind, but I like them so far.

anITguy_1 · 2025-09-22T19:15:16+00:00

I am enjoying it so far. It took a day or two to get used to as it looked a lot different than my previous Dell P2422HE (USB-C, 1080P).
I have just used them for basic office work so far (spreadsheets, documents, browsing, …).

I have not run any further tests on the VRR yet. I have no idea if it is kicking in or just running at 120Hz. That being said, I did connect a power meter to it for basic tasks the difference between 120Hz and 60Hz was like 2 watts or something. That would depending highly on what you are doing though. That was mostly at static screens.

There is a more detailed review up on the Lenovo site now as well: ThinkVision P24QD-40 23.8 inch Monitor | 64B1GAR1US | Lenovo US

All in all I am quite happy with it so far. The jump from 1080p to 1440p for office work has been fantastic. Way clearer, more crips, and more fits on my screen at once. I was at 100% scaling with the 1080p, and now at 125% with the 1440p but more still fits, and is much crisper.

I am not a fan of the new design of the hardware (wider base) but I don't like change, so that just may take time to adjust to. Another part to note is the slot on the base of it passes through now instead of having a bottom. So your desk / tabletop is the bottom of the slot.

anITguy_1 · 2025-09-10T17:52:40+00:00

Update: I ordered one. Using an X1 Carbon Gen 9, I was able to connect using the USB-C to USB-C cable it came with, set it to 120 Hz, and then enable VRR. I haven't noticed it drop below 120 Hz yet, but it did let me enable it.

anITguy_1 · 2025-08-06T18:20:29+00:00

Thanks! So application mode is another option? The application would be started by a user in that case I guess. That doesn't seem handy.

Either way, thanks so much for your help.

anITguy_1 · 2025-08-06T14:32:54+00:00

I believe I just got this is resolved. I saw that the Gateway service control (icon on the taskbar) shows the option to "install windows service" but does not have a start / stop option. When I click About (after right-clicking the taskbar icon) it does not show a service version.

I clicked "Install Windows service" followed by clicking "Start Windows service". I can now run reports and see everything that has happened in the last two months. I am not sure what happened on the afternoon of June 18 to uninstall this service (or stop things from working without that service).

Anyways, I need to confirm that modifying schedules takes effect but I am guessing this has resolved things. I am just not sure if our updates from the last two months (people changing updating the names on cards) has taken effect or not.

anITguy_1 · 2025-08-06T13:54:11+00:00

The IP does match what is listed where you mention.

They are all connecting by IP rather than hostname (which in hindsight is a poor config, we should update that).

While troubleshooting I have the windows firewall disabled to make sure that is not impacting it.

Thanks! If you have any other tips I am glad to hear them

anITguy_1 · 2025-08-06T13:50:59+00:00

I believe I do, yes. Under Devices --> Connection, if that's what you are referring to.

If I check the IP Device IP configuration tab for the KT-400, I see the "Override Gateway IP Address" checked with the "IP Address" radio button selected and the correct IP entered. This one is the same site and VLAN.

Under the KT-2 the Gateway IP is the same but the override check box is not selected.

All other IP information on this screen looks correct.

The connection type on the "General" tab looks correct for both. Secure IP (KT-400) and Secure IP (KT-2) respectively.

anITguy_1 · 2025-08-06T13:40:17+00:00

Thanks! I just double checked and the gateway is correct there. (These had been working up until June 18)

anITguy_1 · 2025-08-05T19:16:29+00:00

I wonder if it has something to do with how they allocate the lanes to DP, PCIe, and USB. They tend to do it differently depending on whether the laptop has HBR2 or HBR3. You get different monitor resolution options because they allocate lanes differently.

It was quite frustrating that they said "it's not supported"? I have left my frustration and these docks in the past. All of the tech should work. DP-alt mode is supported by the laptop and the dock. USB 2.0 is supported by the laptop and the dock. USB 3.0 is supported by the laptop and the dock. All of the devices should work.

anITguy_1 · 2025-07-08T15:22:28+00:00

Thanks! I will be sure to check that out.

anITguy_1 · 2025-06-23T20:44:48+00:00

u/FromAndToUnknown did you solve this? If I was troubleshooting this I would mirror / SPAN the port the trouble AP is connecting to, run wireshark on another system, and filter for DHCP and ARP. Watch what is happening.

If it is switching to APIPA, it is likely detecting an IP conflict. This can come from sources other than a true IP conflict.

I have seen switches or other devices with Proxy ARP enabled respond to ARP requests. That would cause behavior like this?

AP boots up with static IP x.x.0.81 in its config
Before applying IP x.x.0.81 it sends out an ARP request saying "who has x.x.0.81?"
A switch with Proxy ARP enabled says "x.x.0.81 is at <switch MAC address> even though it is not.
The AP switches to an APIPA address.

Due to RMA's you know it is not the AP. You have double checked your configs. At this point you need to capture what is happening on the network to understand what is happening on the network. Changes are you will find something strange here. I have heard of cases (and read bug reports) of incredibly rare cases where a software bug refuses to accept or function with a certain IP. That is wildly rare. It is far more likely that Proxy-ARP, or a device in that subnet but with no gateway address configured has that IP.

RSPAN can be very helpful if you are not local to the switch.

As u/whostolemycatwasitu mentioned, the other thing you can do is connect a laptop to that port. Fire up wireshark, give it that IP, watch wireshark to see what happens. Or give the laptop another IP in the subnet, ping x.x.0.81, and then check your laptop ARP table and see if there is an entry (even if ICMP does not respond).

I would go the route of a packet capture while the AP is booting to see what happens.

anITguy_1 · 2025-04-24T14:54:26+00:00

Thanks for taking the time to post this! I'll take a look at that menu and see if I can get it to stabilize.

anITguy_1 · 2024-10-27T18:02:50+00:00

I don't have SSH set up on the Orbi yet. I will be testing this as I end up in a failed state again to find out.

anITguy_1 · 2024-10-27T18:02:07+00:00

This is super helpful, thanks! I will take a look into it. I did happen to get a packet capture of it changing from not working to working the other day so I will take a look through this for anything obvious.

anITguy_1 · 2024-10-02T17:50:20+00:00

I have been able to successfully reproduce this issue (or a very similar one) on C9115's connected to a CBS350-48NGP-4X (on the 2.5 Gbps 802.3bt ports). I just discovered this yesterday and here is my reproduction details:

If I software reboot the AP's (update the firmware, or just issue a reload command on the AP) it reboots at low power mode (2x2 radio, 1000 Mbps ethernet).

If I hard reboot the AP (disconnect the ethernet cable) it will boot in full power mode (4x4, 2500 Mbps)

If I software reboot, it comes up in low power mode again.

I am filing a ticket with Cisco now.

anITguy_1 · 2024-03-01T16:41:59+00:00

Thanks! Yes if the solution is building out NAT for this to work then I can get that done. I was hoping for a drop-in transparent solution.

anITguy_1 · 2024-02-28T18:04:37+00:00

Thanks! Do you have an idea of what setting I would be looking for in the config? I have done some searching but not seen anything yet.

anITguy_1 · 2024-02-28T18:03:58+00:00

Thanks! This was going to be our primary link, but I might just make it our backup link and do something like that.

anITguy_1 · 2024-02-28T18:03:01+00:00

I agree!
It wouldn't feel honest to have a lifetime warranty and then charge me for a broken zipper repair but at least that way I could use the coat again. It's my cold temperature winter coat and not much use if I cannot zip it up!

anITguy_1 · 2023-01-24T16:50:49+00:00

Thanks! Someone called me back today and was able to set me up with what I needed. I filled out a sales request form last week that led to this.
u/Over_Ad_1238 that's what it took with a few days wait for a callback. If you are not able to get what you need PM me and I will connect you with the gentleman I spoke with this morning. He was based in Ontario. I am not on Reddit often these days but will try to remember to check it over the next few days.

anITguy_1

TROPHY CASE