Who you gonna call? The Blur Busters! For Everything Better Than 60Hz™
https://forums.blurbusters.com/
Hey,
https://forums.overclockers.co.uk/threa ... t-38259889kyube wrote: ↑19 Mar 2026, 10:31Where have you managed to contact Nvidia?
I'm hoping that they:
• Finally unlock full BW to HDMI 2.1 FRL6, instead of FRL5.
• Allow wider duty cycle range (or fix the PW slider?) in ULMB2 mode for 120Hz, 240Hz & 360Hz (so one can push much shorter duration strobe on periods, which is much easier on higher refresh rate)
Sorry for quoting myself but you have to try this. It works so unbelievably well. The display feels so snappy, even panning windows looks and feels clearer than before. I can now play CS2 on Full screen exclusive. I dont see a lower latency on the measuring tools but believe me this is another level. It feels so much better. I can alt-tab in and out as mentioned yesterday. Also retro games like duke nukem (via eduke32) which definitely went black for a short time even on 240 hz when getting to full screen just switch.
None of that matters for writing code to the firmware to pulse the backlight for a specific duration of the refresh rate.brownvim wrote: ↑20 Mar 2026, 04:45https://forums.overclockers.co.uk/threa ... t-38259889
Your math is probably right but seems pixel transition time (GtG) and dark time between pulses are just as important.
That's.... not the case at all.Baddass wrote: 1. it's due to more settling time and is pretty common for lower refresh rates. I had a chat with Mark at Blurbusters about this topic too while I was testing that
There's no "interface timing limtation" at play. Maybe for Pulsar over HDMI, but for normal sample & hold use or ULMB2 use over HDMI, that's nonsensical to me.Baddass wrote: 2. I believe it's an interface timings limitation at the moment and when I queried this with NVIDIA i was told it was deliberate, and that DP is the recommended interface for PC, with HDMI being more suited to multimedia devices.
Thank you very much! Can confirm this worked for me. Can now run the acer monitor at 165hz and 180hz via CRU, and the 360hz mode is indeed disabledmawi wrote: ↑19 Mar 2026, 19:04Hey,
there is a way to force your Nvidia RTX to have (probably) no DSC which brings back the DSR option and even custom resolutions are possible.
You can force your Nvidia only to use single-head.
Open Regedit. Search for:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\
{4d36e968-e325-11ce-bfc1-08002be10318}\
There are some folders in there called:
0000
0001
maybe also 0002
Look which of these folders represents your nvidia by searching the key "DriverDesc". This key should have your GPU name.. Mine is "NVIDIA RTX 4070" on folder 0000.
In this folder, add a new key (DWORD-32) called "EnableTiledDisplay" with value 0.
Then restart.
This will remove the 360 Hz option from your Nvidia menu (as its not possible through single-head). 60, 120 and 240 Hz are still there. Dont worry, pulsar is still working.
Now you can add custom resolutions (not greyed out anymore) and DSR is also listed on Nvidia 3d settings.
I tried adding 8-bit wqhd custom resolution with 300 Hz. WORKS! Unfortunately... not with pulsar anymore. My ASUS Monitor just offers ULMB2 then.
I have tried adding 360 Hz manually, did not work, PC crashed. I did not try 320 etc. If pulsar does not work with "odd" refresh rates, then I dont need them anyway
I am now confident I finally have a non-DSC signal. Maybe this was not the case before...
and NO more alt-tab black screens for me with exclusive full screen. It works so damn well now. Its amazing
The way I understand it (and I could be wrong) is that the longer “strobe off” / dark time at 60 Hz is the main reason why the 60 Hz ULMB mode can often look less blurry — and sometimes even sharper — than the 120/240/360 Hz modes when using the same low pulse width (below ~30).kyube wrote: ↑20 Mar 2026, 07:57None of that matters for writing code to the firmware to pulse the backlight for a specific duration of the refresh rate.brownvim wrote: ↑20 Mar 2026, 04:45https://forums.overclockers.co.uk/threa ... t-38259889
Your math is probably right but seems pixel transition time (GtG) and dark time between pulses are just as important.
Slower G2G RTs than the refresh rate requires don't affect it to that extent either.
I don't understand what you mean with “dark time between pulses”... I assume you've meant the the strobe 'off' period?
As for that person's answers:That's.... not the case at all.Baddass wrote: 1. it's due to more settling time and is pretty common for lower refresh rates. I had a chat with Mark at Blurbusters about this topic too while I was testing that
This can be easily proven by using a oscilloscope + light probe and graphing the strobe 'on' period for every PW setting at different refresh rates & then making a plot of each value.
I expected TFTCentral to do this, but was left disappointed in that aspect
There's no "interface timing limtation" at play. Maybe for Pulsar over HDMI, but for normal sample & hold use or ULMB2 use over HDMI, that's nonsensical to me.Baddass wrote: 2. I believe it's an interface timings limitation at the moment and when I queried this with NVIDIA i was told it was deliberate, and that DP is the recommended interface for PC, with HDMI being more suited to multimedia devices.
Other manifacturers have managed to make their VRR+PWM (ELMB-SYNC, Aim Stabilizer Sync, DyDS 2.0) work over HDMI at full FRL6 bandwidth... which makes that answer from Nvidia even more hillarious.
Nvidia deliberately choose to “partially lock” the HDMI 2.1 port on a scaler IC (MT9810) that's capable of HDMI 2.1 FRL6... a model which costs +700€....
What's funny is that they've went from TMDS to FRL5 with a FW update, so their reasoning is even incoherent to me.
I wouldn't even be surprised if they'd simply pass this artificial limitation under the rug, if someone (me, in this case) didn't mention it.
Perhaps a way to 'force' people to upgrade to 50 series GPUs?....
Unfortunately no but I can still swap back to 240hz when I need to and enable pulsar depending on the game. There's just a few niche games I play that stutter for whatever reason if the current fps doesn't match the max refresh even with gsync enabled.
For some reason, 360hz showed up again as an option but the 165/180hz custom refresh rates are also available...not sure what's going on here now
