How windows calculate refresh rate?

[Worstylolzs]

About the problem:
Hello i got question about how windows calculate refresh rate.
I was reading on this topic viewtopic.php?f=5&t=10044 about how windows calculate refresh rate, and how not rounding it on 360HZ(second post from smorgar).
Week ago i buy 360Hz and i dont have rounded values too.
My 360HZ refresh rate values on my GamingPC:
59,989
119,982
143,981
240,000
299,953
360,113
When i test this monitor on my working laptop, where i have only hdmi 2,0 so i dont have values for 300/360.
Values on working laptop ThinkPad T14 (AMD):
23,976
24,000
50,000
59,940
60,000
119,880
120,000
144,000
240,000

Questions:
1)Why is on my laptop values 60/120/144 rounded or calculated right and on my gaming pc is this wierd values?
I do same test on my other monitor viewsonic 2530gx and again got different values on the both systems like:
Gaming PC:243,964
Working laptom:240,000
2)On gaming pc i do some "Tweaks" In NV_MODES registry and maybe more, because i try to fix frameskipping and wierd frames in my games on my monitor what i use before(viewsonic xg2530) Now i can't boot to safe mode, because i got black screen.... But normal boot is OK. Can reinstal windows help?
3) Can this wierd(not rounded) refresh rate values on 360HZ cause frameskipping, like on 240hz viewsonic xg2530? Topic here: viewtopic.php?f=2&t=3598&hilit=frameskipping
4) What Nvidia registry NV_MODES exatly do?

Thank you very much for future replies.

[ToastyX]

Windows gets the refresh rates from the GPU's driver, and the GPU's driver gets the refresh rates from the monitor's EDID. Historically, Windows could only list refresh rates as integers, so 123.456 Hz would be listed as 123 Hz. Newer versions of Windows can list fractional refresh rates, but the GPU's driver has to report the fractional part. NVIDIA's driver reports the actual refresh rate with the fractional part, while AMD's driver still only reports the refresh rate rounded to the nearest integer except for the automatically added TV refresh rates (23.976/59.94/119.88 Hz). That doesn't affect the actual refresh rate, only how it's listed in the display settings. That's unrelated to the frame skipping issue, which is a firmware bug in certain monitors.

NV_MODES is just a list of default resolutions added by NVIDIA's driver. For monitors with an EDID, NVIDIA's driver only uses NV_MODES to add scaled resolutions.

[Worstylolzs]

Windows gets the refresh rates from the GPU's driver, and the GPU's driver gets the refresh rates from the monitor's EDID. Historically, Windows could only list refresh rates as integers, so 123.456 Hz would be listed as 123 Hz. Newer versions of Windows can list fractional refresh rates, but the GPU's driver has to report the fractional part. NVIDIA's driver reports the actual refresh rate with the fractional part, while AMD's driver still only reports the refresh rate rounded to the nearest integer except for the automatically added TV refresh rates (23.976/59.94/119.88 Hz). That doesn't affect the actual refresh rate, only how it's listed in the display settings. That's unrelated to the frame skipping issue, which is a firmware bug in certain monitors.

NV_MODES is just a list of default resolutions added by NVIDIA's driver. For monitors with an EDID, NVIDIA's driver only uses NV_MODES to add scaled resolutions.

Thanks for answer! Im happy for this can't cause frameskipping and got some new infos.
I got another one, how the windows get what is default resolution of the monitor? Because on this 360hz alienware 2521h i got default 1920x1080 with 360hz, but on viewsonic xg2530 i have got default resolution 1920x1080 HD/TV (Idk right now, but was not clasic 1920x1080 like on 360) what got max 120HZ. Its the same like with refresh rate?
Thanks!

[ToastyX]

I got another one, how the windows get what is default resolution of the monitor? Because on this 360hz alienware 2521h i got default 1920x1080 with 360hz, but on viewsonic xg2530 i have got default resolution 1920x1080 HD/TV (Idk right now, but was not clasic 1920x1080 like on 360) what got max 120HZ. Its the same like with refresh rate?

I don't understand what you're asking. Where are you seeing this?

[Worstylolzs]

I got another one, how the windows get what is default resolution of the monitor? Because on this 360hz alienware 2521h i got default 1920x1080 with 360hz, but on viewsonic xg2530 i have got default resolution 1920x1080 HD/TV (Idk right now, but was not clasic 1920x1080 like on 360) what got max 120HZ. Its the same like with refresh rate?

I don't understand what you're asking. Where are you seeing this?

Sry for not better specify. I mean showing default refresh rate in Nvidia control panel---> Refresh rate, where you can see on refresh rate text (default)

RefreshRateCz.PNG (75.77 KiB) Viewed 3089 times

I got control panel in Czech. (základní) means (Default)

[ToastyX]

The first detailed resolution in the EDID as shown in CRU is considered the preferred or native resolution. In the English version, I see "(native)" next to the resolution in the NVIDIA control panel and "(Recommended)" in the Windows display settings. Windows doesn't have a default or native refresh rate.

PC vs. HD/SD is NVIDIA-specific, not part of Windows. The NVIDIA control panel lists resolutions with timing parameters matching the CTA-861 standard under HD/SD, which are commonly used with HDTVs. I think that's confusing because sometimes a resolution will be listed in both places with some refresh rates under PC and others under HD/SD.