So, after trialling the BenQ PD3225U 4K monitor with my new Mac Studio M4 Max, I am comparing it with the PD3226G 4K. I have 2 immediate questions:
1) the monitor is 144Hz, so why can I only set it to 100Hz in Settings>Display?
2) HDR is not available unless I lower the frequency from 100Hz to 60Hz. Is this correct?
Thanks in advance.
[Re-Titled by Moderator]
Mac Studio, macOS 15.3
<< 1) the monitor is 144Hz, so why can I only set it to 100Hz in Settings>Display? >>
Because there is not enough bandwidth in a typical Thunderbolt cable to run any faster than what you are achieving.
<< 2) HDR is not available unless I lower the frequency from 100Hz to 60Hz. Is this correct? >>
Yes, because there is not enough bandwidth in a typical ThunderBolt cable to do that.
If you want the data rates you are asking about, the Thunderbolt cable has to 'gear-shift' from its current HBR3, about 26 G bits/secs up to the next step, UHBR10, which runs just shy of maximum outbound speed of 40 G bits/sec.
This is ONLY possible with Thunderbolt cables shorter than 0.5 meters, or with tuned ACTIVE cables that cost a lot more.
<< I am getting nominal 4K (3840x2160) and HDR at 144Hz. >>
You did NOT appear to post that you could attain that resolution and refresh rate previously.
if you had, I would have referred you to the footnote(c)
c) Although this format slightly exceeds the maximum data rate of this transmission mode with CVT-R2 timing, it is close enough to be achieved with non-standard timings
so the answer is, you got through because that specific timing can be an exception sometimes.
<<. I am connecting via a genuine Thunderbolt cable. >>
and is that cable 0.5 meters or shorter?
I am having no problem reading your posts -- I have my Forums settings for chronological order -- perhaps yours is set to something different?
I read the resolutions you posted. Each and every once conforms with what is expected with the setup you have.
Resolution, refresh rate, and number of bits/color all conspire to drive up the overall data rate required. With the computer, the cables, and the display you have, you have now successfully enumerated what is possible.
I have also stated what it would take to get the rates you desire.
Sorry, I don't understand.
Why would the highest res, i.e. 3560x2160, allow the most options - 144Hz and HDR? I would logically think that the highest res would be making the most demands on data bandwidth.
I'm still struggling with this, sorry.
I just cannot see why lower resolutions are more restricted in refresh rates and HDR in Settings>Display. Makes no sense to me despite your best attempts to explain.
In games, I can get 144fps in 4K, but only 100fps in resolution below that, i.e. 3360x1890 (and no HDR). Completely counter-intuitive to me.
What tables are you referring to?
‘4k 8 bits color 120 Hz
4K, 10 bits color 100 Hz’
But the point is, I am getting 144Hz in 4K HDR10!
I’m confused by the table. Surely that’s for DP. I’m running on Thunderbolt 5 from Mac to Thunderbolt 4 on monitor.
Thanks again for all your time.
I think your responses are too technical for me, and maybe I’m not explaining myself well enough.
I’ll try to put my question as simply as I can:
Why do I get 144Hz HDR at native res, yet I can’t at lower values?
As an aside, the common definition of ‘4K’ is 3840x2160 and that is why I use the term. Obviously, that is not 4K pixels. Similarly, ‘5K’ is not 5K pixels. AFAIK, these terms are just lazy ways of defining the horizontal resolution.
Regarding ‘Thunderbolt’, I was just explaining the port situation, i.e. TB5 port on Mac to TB4 on monitor. I wasn’t suggesting I was running on TB5.
So, I think from your reply, this is where we have the confusion. I am getting nominal 4K (3840x2160) and HDR at 144Hz, and I am not getting it at lower resolutions like 3360x1890, where it is restricted to 100Hz and no HDR. This is the reason for my question from the start.
Please see attached.
Sorry, but I posted it several times. Look at my 3rd post on page one for the first time, and several posts after that.
I don't know if we've come to the end of the road here, but I still have no idea why higher refresh rates and HDR are available at higher resolutions, but not in lower ones.
I think I'll approach BenQ and Apple support. If I find out anything useful I'll post back here.
So, I have had quite a few exchanges with BenQ support on this, and I would say that they are pretty baffled. They have been extremely responsive and helpful, but the engineers are scratching their heads a bit.
They can't understand why the full HDR and 144Hz options are available at the highest resolution and not with some of the lower ones.
I'm waiting on their latest thoughts on the subject.
imacken wrote:
Thanks for that.
Could you explain why 3360x1890 goes to 6720x3780 and the 2160p doesn’t go higher?
If your display has a native resolution of 3840x2160 pixels, and you select a Displays Settings "resolution" of 3360x1890 pixels, the computer has two choices:
If your display has a native resolution of 3840x2160 pixels, and you select a Displays Settings "resolution" of 3840x2160 pixels, then a NON-Retina 3840x2160 pixel canvas already has as much detail as your display is capable of displaying. Drawing on a 7680x4320 (8K) canvas, and then downscaling that back to 3840x2160 pixels (to fit the 3840x2160 pixel display) would essentially be a lot of "make work" for no gain.
I believe this is why, if you tell Displays Settings to show all resolutions, as a list, you'll see both Retina choices, and "(low resolution)" choices, for many resolutions – but only one choice for your display's native resolution.
For that resolution, only non-Retina mode makes sense.
Thanks. Forgot to mention I am connecting via a genuine Thunderbolt cable.
I really appreciate the time you are taking to answer here.
Can you in simple terms, tell me why I can get 144Hz HDR at 3560x2160, but only 100Hz no HDR at 3360x1890?
Thanks.
I have just tried out a 0.5m Thunderbolt 4 cable, and there is no change to the situation.
Thanks for that.
Could you explain why 3360x1890 goes to 6720x3780 and the 2160p doesn’t go higher?
Mac Studio M4 Max and BenQ PD3226G Display: HDR and Refresh Rate Limitations
