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AMD/ATI Pixel Clock Patcher
11-08-2019, 09:39 PM (Last edited: 11-08-2019, 09:45 PM by Trendle)
Post: #931
RE: AMD/ATI Pixel Clock Patcher
(11-08-2019 04:24 PM)ToastyX Wrote:  
(11-08-2019 03:15 PM)Trendle Wrote:  Quick question: will this patch remove the 600 MHz limit that I'm currently seeing on this monitor?
No. Is that with DisplayPort or HDMI 2.0?

The range limits pixel clock must be a multiple of 10 MHz.

Sorry for the delayed response; it's DP 1.2. I increased the pixel clock limit to 630 MHz, but it doesn't seem to be working because I can't apply anything that goes above 600 MHz. Huh
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11-09-2019, 12:45 AM
Post: #932
RE: AMD/ATI Pixel Clock Patcher
(11-08-2019 09:39 PM)Trendle Wrote:  Sorry for the delayed response; it's DP 1.2. I increased the pixel clock limit to 630 MHz, but it doesn't seem to be working because I can't apply anything that goes above 600 MHz. Huh
What video card do you have?
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11-09-2019, 12:50 AM
Post: #933
RE: AMD/ATI Pixel Clock Patcher
(11-09-2019 12:45 AM)ToastyX Wrote:  
(11-08-2019 09:39 PM)Trendle Wrote:  Sorry for the delayed response; it's DP 1.2. I increased the pixel clock limit to 630 MHz, but it doesn't seem to be working because I can't apply anything that goes above 600 MHz. Huh
What video card do you have?

R9 280X.
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11-09-2019, 12:56 AM
Post: #934
RE: AMD/ATI Pixel Clock Patcher
(11-09-2019 12:50 AM)Trendle Wrote:  R9 280X.
Older AMD cards only support up to 600 MHz pixel clock with DisplayPort 1.2.
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11-09-2019, 01:00 AM
Post: #935
RE: AMD/ATI Pixel Clock Patcher
(11-09-2019 12:56 AM)ToastyX Wrote:  
(11-09-2019 12:50 AM)Trendle Wrote:  R9 280X.
Older AMD cards only support up to 600 MHz pixel clock with DisplayPort 1.2.

Really? Wow, I'm surprised. Is that an artificial limitation? May I ask where you found this info? I'm interested in reading about it.

Thank you so much for your replies.
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11-09-2019, 02:22 AM
Post: #936
RE: AMD/ATI Pixel Clock Patcher
(11-09-2019 01:00 AM)Trendle Wrote:  Really? Wow, I'm surprised. Is that an artificial limitation? May I ask where you found this info? I'm interested in reading about it.
Strangely, I can't find any reference to this except for my own posts, so I don't remember where I got it from. I just remember people running into this limit before, but it's possible the driver is just applying the original limit defined in the range limits. I don't have a way to test if this limit can be bypassed. I do know for sure that NVIDIA Kepler GPUs are limited to 540 MHz pixel clock, so limits with older cards are not unheard of.
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11-09-2019, 12:14 PM
Post: #937
RE: AMD/ATI Pixel Clock Patcher
(11-09-2019 02:22 AM)ToastyX Wrote:  
(11-09-2019 01:00 AM)Trendle Wrote:  Really? Wow, I'm surprised. Is that an artificial limitation? May I ask where you found this info? I'm interested in reading about it.
Strangely, I can't find any reference to this except for my own posts, so I don't remember where I got it from. I just remember people running into this limit before, but it's possible the driver is just applying the original limit defined in the range limits. I don't have a way to test if this limit can be bypassed. I do know for sure that NVIDIA Kepler GPUs are limited to 540 MHz pixel clock, so limits with older cards are not unheard of.

That's very unfortunate. As far as testing if the limit can be bypassed, is that a complicated process? I'm asking because I would do this myself, if possible.
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11-09-2019, 02:49 PM
Post: #938
RE: AMD/ATI Pixel Clock Patcher
(11-09-2019 12:14 PM)Trendle Wrote:  That's very unfortunate. As far as testing if the limit can be bypassed, is that a complicated process? I'm asking because I would do this myself, if possible.
The first thing I would need to know is what happens if you connect a DisplayPort 1.2 monitor that defines a max pixel clock greater than 600 MHz. If it's still limited to 600 MHz, then the driver is enforcing a fixed pixel clock limit defined either in the driver or by the video card, possibly because of a hardware limitation. If it allows more than 600 MHz, then it's more likely to be an artificial limitation imposed by the driver. Either way, it would be hard to find where in the driver this is happening because it's binary and there's no source code. I haven't had any luck getting around DisplayPort limits, even ones that I know are artificial. For example, there's an adapter I know that's capable of 357/476 MHz pixel clock but is limited to 300/400 MHz pixel clock on AMD cards, and I haven't found a way around that.
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11-09-2019, 03:09 PM (Last edited: 11-09-2019, 03:11 PM by Trendle)
Post: #939
RE: AMD/ATI Pixel Clock Patcher
(11-09-2019 02:49 PM)ToastyX Wrote:  
(11-09-2019 12:14 PM)Trendle Wrote:  That's very unfortunate. As far as testing if the limit can be bypassed, is that a complicated process? I'm asking because I would do this myself, if possible.
The first thing I would need to know is what happens if you connect a DisplayPort 1.2 monitor that defines a max pixel clock greater than 600 MHz. If it's still limited to 600 MHz, then the driver is enforcing a fixed pixel clock limit defined either in the driver or by the video card, possibly because of a hardware limitation. If it allows more than 600 MHz, then it's more likely to be an artificial limitation imposed by the driver. Either way, it would be hard to find where in the driver this is happening because it's binary and there's no source code. I haven't had any luck getting around DisplayPort limits, even ones that I know are artificial. For example, there's an adapter I know that's capable of 357/476 MHz pixel clock but is limited to 300/400 MHz pixel clock on AMD cards, and I haven't found a way around that.

Okay, thanks. I "need" a GPU upgrade anyway, so I guess I'll go with that. It's a shame that good video cards are so expensive these days. Undecided Oh well.
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11-09-2019, 04:03 PM
Post: #940
RE: AMD/ATI Pixel Clock Patcher
(11-09-2019 03:09 PM)Trendle Wrote:  Okay, thanks. I "need" a GPU upgrade anyway, so I guess I'll go with that. It's a shame that good video cards are so expensive these days. Undecided Oh well.
If it's listening to the range limits and won't let you override it, then a new video card won't help either unless you go NVIDIA. Do you know if the monitor can even handle a pixel clock greater than 600 MHz?
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