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
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?
HBR2 is the speed you can can get on a USB connection when the cables are under a meter. The basic rate is 10 G bits/sec, and then it 'turns around' and runs the inbound lanes as outbound lanes part of the time, to get a speed of 17.28 (less than the nominal 20 max).
HBR3 requires a Thunderbolt cable, which effectively runs twice as fast as USB. When you try to run a one meter ThunderBolt cable as high as UHBR10 data rate, it makes too many errors and falls back to the slower HBR3 speed. You need a 0.5 meter Thunderbolt cable, or an ACTIVE cable to get the top data rate.
‘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.
you are NOT running 4K, you dropped your row width much lower. 3840-3560 is 280 columns of data, times 2160 * [10 bit Bytes] each! That's 6,048,000 bits PER FRAME * whatever refers rate -- not trivial -- and maybe that's what lets you get in under the wire.
when you are running "ThunderBolt" the protocol you are actually running is DisplayPort-over-Thunderbolt.
ThunderBolt 5 only adds speed when the Port, the cable, and the external device ALL support Thunderbolt-5. Otherwise, it is running at ThunderBolt 3-4 speeds.
<< Why do I get 144Hz HDR at native res, yet I can’t at lower values? >>
you don't get nominal 4K at HDR at 144 Hz. You only get that when you drop the screen size lower than 3840 wide -- to 3560 is what you wrote.
You are able to achieve that because these display protocols do not increase their speeds by a few GHz/second when you increase the resolution by a few pixels. There are several fixed overall transmission speeds {HBR, HBR2, HBR3, UHBR10}. If your data fits inside one of the envelopes, it runs. if not, you have to reduce resolution or refresh rate.
<< 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.
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.
Latest response from BenQ support says:
‘Regarding why 1920 x1080 at 144Hz shows up while the monitor only supports up to 120Hz at this resolution, we have confirmed that this is a MacOS issue. When set to 1920 x 1080, the signal out put from Mac is still at 3840 x 2160, and the refresh rate is supported up to 144Hz at that resolution. In other words, due to the way MacOS works, the monitor is still detecting 3840 x 2160 from the source computer.
This is the same behavior on Mac's native screen if you change resolution settings, if you set at 3840x2160, everything on the screen looks smaller, but if set to a lower resolution, everything is then scaled up, but the actual resolution is still at the panel's native resolution.
And we have also observed that when selected the resolution from 2304x1296 to 3360x1890, the Mac's image is double pixel, so HDR cannot be selected, as there is not enough bandwidth left in this situation.
At the moment, as the issue is mainly caused by how Mac devices work with resolution, there is nothing we can do to improve the behavior. But you can rest assured that our team has requested Apple for some more information to follow up with the issue. We would encourage you to also contact Apple directly for further assistance on the issue.’
I think that is pretty much what 'Servant of Cats' said above.
imacken wrote:
Latest response from BenQ support says:
‘Regarding why 1920 x1080 at 144Hz shows up while the monitor only supports up to 120Hz at this resolution, we have confirmed that this is a MacOS issue. When set to 1920 x 1080, the signal out put from Mac is still at 3840 x 2160, and the refresh rate is supported up to 144Hz at that resolution. In other words, due to the way MacOS works, the monitor is still detecting 3840 x 2160 from the source computer.
I would definitely expect things to work that way if you were running a 3840 x 2160 pixel monitor in Retina "like 1920 x 1080" mode. In that mode, things are being sized "as if" the monitor had 1920 x 1080 "workspace", but things are actually being drawn at a 3840 x 2160 pixel level of detail.
If you go into Displays Settings, and display all resolutions as a list, and choose "1920 x 1080 (low resolution)", I am not sure whether the Mac would send a 1920 x 1080 signal to the monitor – or whether it would still send the monitor a 3840 x 2160 signal, albeit in this case, one with only 1920 x 1080 pixels' worth of actual detail.
I am surprised that the monitor supports a higher refresh rate for 3840 x 2160 than for 1920 x 1080!
it appears that the PD3226G display you mentioned DOES support HDMI 2.1.
It would provide higher resolutions over HDMI. This REQUIRES certified ULTRA HDMI cables, which are backward-compatible.
Thanks. Forgot to mention I am connecting via a genuine Thunderbolt cable.
<<. I am connecting via a genuine Thunderbolt cable. >>
and is that cable 0.5 meters or shorter?
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.
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
