[SOLVED] Need help: Cant change refresh rate from 120hz to 165hz

[Grego12]

Hi everyone,


Im sure you guys have dealt with this a million times. But I've spent hours trying to figure it out. I cant get my monitor to show 144hz or 165 hz. It seems 120hz is the max, but i know my GPU supports at least 144hz.

Specs:
LG 27GP83B (this monitor should go up to 165hz)
XFX R9 380X
i5-4690k
32gig ram

Im using the supplied display port cable.
I have reinstalled AMD driver, and have installed the monitor driver.

Any ideas why I cant get 144hz or 165hz?

 

[SenatorSlime]

I had this same problem. It is likely that your HDMI or Display port cable is bottlenecking the connection. To fix this, buy a better cable. If you are using HDMI then you need to buy a HDMI 1.4 or higher cable (I may be incorrect on this, if you want to be extra safe just get a HDMI 2.1 cable) . If you are using Display port you will need Display port 1.2 or higher. I recommend using display port if your GPU and monitor both have a display port plug in. Also check the display port cable you are currently using to see if it has 1.2 or higher on it.

 

[Grego12]

I had this same problem. It is likely that your HDMI or Display port cable is bottlenecking the connection. To fix this, buy a better cable. If you are using HDMI then you need to buy a HDMI 1.4 or higher cable (I may be incorrect on this, if you want to be extra safe just get a HDMI 2.1 cable) . If you are using Display port you will need Display port 1.2 or higher. I recommend using display port if your GPU and monitor both have a display port plug in. Also check the display port cable you are currently using to see if it has 1.2 or higher on it.

Thanks for the response.
On a $450 monitor, the displayport cable that comes in the box cant do 144hz?!
Thats a huge cheeseball move by LG if thats the case. I cant see anywhere on the cable if its 1.2 or 1.4, but there is a tag saying it can do 5K if that helps.
Im still looking for info online about the version of the cable.

 

[SenatorSlime]

I'm not an expert on this (or anything really), so I could be wrong. I will look into a possible alternative cause for the problem. If I find anything I will let you know. The cable may be able to run 5k at 60hz, but cant run 1080p at 144hz, but I doubt that is the case.

Edit: just realized your monitor is 1440p, the cable versions I listed in my previous response might be incorrect. also given the fact that the monitor is 1440p, it is possible that the cable they gave you can run 5k at 60hz, but not 1440 at 144hz

 

[Grego12]

I'm not an expert on this (or anything really), so I could be wrong. I will look into a possible alternative cause for the problem. If I find anything I will let you know. The cable may be able to run 5k at 60hz, but cant run 1080p at 144hz, but I doubt that is the case.

Edit: just realized your monitor is 1440p, the cable versions I listed in my previous response might be incorrect. also given the fact that the monitor is 1440p, it is possible that the cable they gave you can run 5k at 60hz, but not 1440 at 144hz

Thanks senator. I appreciate the help.
I ordered a vesa 1.4 cable as im fed up researching the problem.
I bet you're right about the cable in the box though!

 

[Glenwing]

R9 380X only supports DisplayPort 1.2, which is maximum HBR2 speed. 1440p at 165 Hz with 10 bpc color depth requires HBR3 speed, which your graphics card does not support. The cable is not the issue.

 

[Grego12]

R9 380X only supports DisplayPort 1.2, which is maximum HBR2 speed. 1440p at 165 Hz with 10 bpc color depth requires HBR3 speed, which your graphics card does not support. The cable is not the issue.

This seems to be correct.
However, when I switch to 8-bit in the radeon software, I am still limited to 120hz. But it should go to 144hz.

 

[Bob.B]

R9 380X only supports DisplayPort 1.2, which is maximum HBR2 speed. 1440p at 165 Hz with 10 bpc color depth requires HBR3 speed, which your graphics card does not support. The cable is not the issue.

In theory dp 1.2 supports 1440p@165 however you need to read the fine print.
https://en.wikipedia.org/wiki/DisplayPort#Resolution_and_refresh_frequency_limits

 

[Glenwing]

In theory dp 1.2 supports 1440p@165 however you need to read the fine print.
https://en.wikipedia.org/wiki/DisplayPort#Resolution_and_refresh_frequency_limits

Not at 10 bpc color depth, which I included in my statement.

 

[Bob.B]

Not at 10 bpc color depth, which I included in my statement.

True....part of that fine print stuff.

 

[Grego12]

Not at 10 bpc color depth, which I included in my statement.

Does dp1.2 support 10 bit 1440p 144hz? I am unsure from reading the wiki page.

 

[Glenwing]

Does dp1.2 support 10 bit 1440p 144hz? I am unsure from reading the wiki page.

Some monitors do (my LG 27GL850 runs 1440p 144 Hz 10 bpc with only HBR2 speed) but it depends on how the monitor's timings are configured, which is product-specific. Some monitors will be limited to 120 Hz.

 

[Grego12]

Some monitors do (my LG 27GL850 runs 1440p 144 Hz 10 bpc with only HBR2 speed) but it depends on how the monitor's timings are configured, which is product-specific. Some monitors will be limited to 120 Hz.

Thanks for this info.
I can’t find any info in the manual about the timings.

Did you get the 144hz 1440p 10bit from the included display cable? I’m deciding whether a better cable would help.

 

[Glenwing]

Did you get the 144hz 1440p 10bit from the included display cable? I’m deciding whether a better cable would help.

A better cable won't change anything in this case. If you're able to run 120 Hz then it's working fine at HBR2 transmission speed, the signal speed doesn't change based on the format, so it is not a cable issue preventing you from going higher.

Thanks for this info.
I can’t find any info in the manual about the timings.

It's not often listed there (you would need to examine the monitor EDID), although they do give the horizontal refresh frequency for each mode in the manual. They don't give the pixel rate so it isn't enough for me to deduce what the timings are, but I can see that their 1440p 144 Hz format runs at 219 kHz horizontal frequency which is higher than my 27GL850 (which runs at 215 kHz), so yours takes slightly more bandwidth and probably doesn't fit within the limits of HBR2 speed.

 

[Grego12]

A better cable won't change anything in this case. If you're able to run 120 Hz then it's working fine at HBR2 transmission speed, the signal speed doesn't change based on the format, so it is not a cable issue preventing you from going higher.


It's not often listed there (you would need to examine the monitor EDID), although they do give the horizontal refresh frequency for each mode in the manual. They don't give the pixel rate so it isn't enough for me to deduce what the timings are, but I can see that their 1440p 144 Hz format runs at 219 kHz horizontal frequency which is higher than my 27GL850 (which runs at 215 kHz), so yours takes slightly more bandwidth and probably doesn't fit within the limits of HBR2 speed.

Ok thank you. Ill enjoy 120hz until I get a better GPU then!

 

[Jacob 51]

Hi everyone,


Im sure you guys have dealt with this a million times. But I've spent hours trying to figure it out. I cant get my monitor to show 144hz or 165 hz. It seems 120hz is the max, but i know my GPU supports at least 144hz.

Specs:
LG 27GP83B (this monitor should go up to 165hz)
XFX R9 380X
i5-4690k
32gig ram

Im using the supplied display port cable.
I have reinstalled AMD driver, and have installed the monitor driver.

Any ideas why I cant get 144hz or 165hz?

Change resolution to PC NATIVE.
There's two types of 1440p, which might be in your AMD radeon control panel. You have to choose the one that says "native" next to it.
In the NVIDIA control panel, it appears like this:

https://imgur.com/a/BN65B1r

View: https://imgur.com/a/BN65B1r


If you're on the other 1440p (non native), it will only give upto 120 hz.

 

[Glenwing]

Change resolution to PC NATIVE.
There's two types of 1440p, which might be in your AMD radeon control panel. You have to choose the one that says "native" next to it.
In the NVIDIA control panel, it appears like this:

If you're on the other 1440p (non native), it will only give upto 120 hz.

This is just an organizational problem that is specific to NVIDIA. "Native" format in the NVIDIA control panel just means whichever format is listed first in the EDID, whereas CTA-861 standard formats (60 Hz, 120 Hz) are separated into the "UHD, HD, and SD" section for no apparent reason, even when they are the same resolution. This doesn't apply to AMD systems (or to selecting from the Windows settings) since they don't make the same arbitrary organization split that NVIDIA does.