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Overclocking BENQ XL2420T v1 (120hz version)

Posted: 02 Oct 2020, 10:00
by mintys
Hey everybody.
So I have a benq xl2420t @ native 120hz that recently bought for 40$. Ive done some research and realized there's actually 2 version of this model: the 120hz version (wich i have) and a 144hz version.
Im trying to overclock my monitor to 144hz but the highest i get is 130hz with "CVT reduced blank" on NVIDIA Control Panel
Im pretty new with overclocking monitors so i need a little advice to get 144hz.

pd: sorry for broken english lol

Re: Overclocking BENQ XL2420T v1 (120hz version)

Posted: 24 Nov 2020, 16:54
by denexter3
Depends what interface you use. Is it HDMI or DVI?
DVI is normally unable to handle this resolution, while HDMI depends on its version.

If you have DVI, use CRU (Custom Resolution Utility), do everything the same way, but choose "Timing" as "LCD Reduced".
This will decrease the blanks even more, and make it so DVI-D DL can actually handle the entire signal.

Re: Overclocking BENQ XL2420T v1 (120hz version)

Posted: 24 Nov 2020, 23:12
by Chief Blur Buster
Also try "Manual" and shrink numbers even smaller than LCD Reduced. Try a Horizontal Total of as small as 1944 pixels (8 pixels each for the horizontal porches/sync) and 1083 pixels (1 pixel each for the vertical porches/sync).

The BenQ monitors are usually Pixel Clock limited in overclocks -- the number of pixels per second transmitted over the cable. There are offscreen pixels used in porches and sync. To help you understand the bandwidth budget you're working with -- this is what CRU numbers look like when spatially mapped out on a signal.

Image

Shrink all of those offscreen paddings (porches/sync) and you can sometimes get even more refresh cycles per second into the same bandwidth budget.

A monitor is often the same number of pixels per second, so you want to shrink those porches/sync to get more refresh cycles per total number of pixels per second (Pixel Clock).