I bought a fake 600hz monitor, help.

[radeko]

TRY UFO test MPRT indicator. I gave instructions in the post above.

[F1zus]

TRY UFO test MPRT indicator. I gave instructions in the post above.

I checked the monitor on your advice and the first digit at the initial speed of 480 Pixel/sec is 3.3ms (when turning on the 600Hz refresh rate), on my old 240Hz monitor the initial figure is 4.4ms.

[radeko]

Add overdrive .maybe the results will improve
Don't take screenshots. It won't help us at all.

[F1zus]

Tell me, is there a way to use a phone camera to find out what the monitor's actual refresh rate is?

Indeed there is:

https://testufo.com/frameskipping

Make sure to read the instructions on that page.

Yes, indeed. At 240Hz, I see 16 squares in a row, but at 280Hz, there are already gaps in the row of squares, and at 600Hz, they start going from top to bottom, not from right to left as usual. Look at the first photo: 600Hz, and the second: 240hz.

[F1zus]

Add overdrive .maybe the results will improve
Don't take screenshots. It won't help us at all.

This is a terrible monitor. Just look at how it skips pixels at a refresh rate above 240Hz. It's simply unusable. Now I understand why it's so cheap. I bought it for about $442.
I've now written to the seller about a return. Either the timings in the CRU are incorrect, or it's an overclocked panel with a true refresh rate of 240Hz. Never buy the AG248F, it's a fake!!! They're simply selling you an outdated 240Hz panel with modified firmware. These unknown Chinese manufacturers are scamming people!

[radeko]

$442 is expensive. $150 is price of AOC 25G4SXU (310 hz) wide gamut ips. with good gtg at 240hz

[RealNC]

Okay, I set the shutter speed to 1/15th of a second, took a photo, and there are no missing pixels. I see 17 white squares arranged one after the other. But how do I know the actual refresh rate is 600Hz, and not 240Hz, for example? It seems to me that the Chinese manufacturer modified the monitor's firmware, and it actually has a native 240Hz matrix, and it actually refreshes at 240Hz, but the software shows 600Hz, both in tests and in CRU.
Initially, the FPS in this test equals your monitor's refresh rate. But since the refresh rate may be fake, the FPS will be 600 in the test, while the actual refresh rate is 240. In this scenario, will the test be able to determine the monitor's actual refresh rate?

The test measures the refresh rate from the GPU side though the vblank interval. If it says 600, it means the monitor is accepting a 600Hz signal.

"Fake" refresh rates are done by accepting high refresh rate input, but the panel actually refreshes at a lower rate. In that case, you will see frame skipping, which manifests as black squares on that test.

Looks like you've been scammed.

[MSIfanboy]

Add overdrive .maybe the results will improve
Don't take screenshots. It won't help us at all.

This is a terrible monitor. Just look at how it skips pixels at a refresh rate above 240Hz. It's simply unusable. Now I understand why it's so cheap. I bought it for about $442.
I've now written to the seller about a return. Either the timings in the CRU are incorrect, or it's an overclocked panel with a true refresh rate of 240Hz. Never buy the AG248F, it's a fake!!! They're simply selling you an outdated 240Hz panel with modified firmware. These unknown Chinese manufacturers are scamming people!

did you even try the cru timings i posted?

[F1zus]

Add overdrive .maybe the results will improve
Don't take screenshots. It won't help us at all.

This is a terrible monitor. Just look at how it skips pixels at a refresh rate above 240Hz. It's simply unusable. Now I understand why it's so cheap. I bought it for about $442.
I've now written to the seller about a return. Either the timings in the CRU are incorrect, or it's an overclocked panel with a true refresh rate of 240Hz. Never buy the AG248F, it's a fake!!! They're simply selling you an outdated 240Hz panel with modified firmware. These unknown Chinese manufacturers are scamming people!

did you even try the cru timings i posted?

Yes, I've tried a bunch of timings, and I'm seeing pixel skipping at all of them. Anything above 240Hz simply doesn't work properly at any timing. Moreover, the higher the refresh rate, the more pixel skipping occurs. I went into the monitor's service menu, and it listed the M241HTN01.9 matrix, which is a lie. As I discovered, it's not even a TN panel, as the viewing angles are very wide, especially when looking down. TN matrices always distort viewing angles. This monitor has some IPS panel with a native 240Hz refresh rate and modified firmware, into which the Chinese manufacturer has written parameters from a 600Hz monitor. This is complete nonsense, as I was able to overclock it to 800Hz in 1440x1080 mode and, naturally, the smoothness was worse than at 240Hz. If you connect the cable to the second DP port, the monitor is detected as 3840x2160@144Hz, naturally with very low scaling, resulting in a blurry picture. Essentially, I wasted $442... Some Chinese guy scammed me. I had no idea they were still doing this in 2026. They used to counterfeit Nokia and Sony Ericsson phones, then moved on to SSDs and flash drives, and now they've gotten around to monitors. I'll try to return it.

[Chief Blur Buster]

I checked the monitor on your advice and the first digit at the initial speed of 480 Pixel/sec is 3.3ms (when turning on the 600Hz refresh rate), on my old 240Hz monitor the initial figure is 4.4ms.

You can't use screenshots or photos for this -- you need to eyetrack your eyes and speed up the motion until you see some blocks overlapping vs not overlapping.

But, frameskipping test is actually more important here, which you did:

Okay, I set the shutter speed to 1/15th of a second, took a photo, and there are no missing pixels. I see 17 white squares arranged one after the other. But how do I know the actual refresh rate is 600Hz, and not 240Hz, for example? It seems to me that the Chinese manufacturer modified the monitor's firmware, and it actually has a native 240Hz matrix, and it actually refreshes at 240Hz, but the software shows 600Hz, both in tests and in CRU.
Initially, the FPS in this test equals your monitor's refresh rate. But since the refresh rate may be fake, the FPS will be 600 in the test, while the actual refresh rate is 240. In this scenario, will the test be able to determine the monitor's actual refresh rate?

If www.testufo.com/frameskipping says "600fps" and "600Hz" and says green READY and you have no gaps in the photos == you definitely have 600 Hz. But if you have gaps like in the photo = it's fake.

Originally I was wondering about LCD GtG taking several refresh cycles, meaning you can't easily tell apart refresh rates above approximately 100-200Hz(ish) except for the reduced stroboscopic stepping effects (www.testufo.com/mousearrow) -- but this is not the case here.

Instead, your newer photos shows a fake 600Hz, showing only 240 out of 600 cable-delivered refresh cycles per second.