Lightboost with low FPS - Leave on or turn off?

[K3D]

Hi,

If I'm using strobed 120 FPS with a game running at 45 FPS what will happen? I'm used to Strobed Lightboost colors (usually play games that are above 120 FPS), and I'm curious if you guys would recommend leaving it on or turning it off...

[flood]

leave it off
if you have strobing on youll see double/triple image effects when you move your eyes to track something moving

[Falkentyne]

TBH it doesn't matter.
If you have it on, you'll get double/triple image effects
if you have it off, you'll get a massively blurry mess.
the real issue is lightboost is best if you use Vsync, and if your FPS drops that low with vsync, you usually get a lot of input lag.
if you never get refresh rate=hz at all, though, then there's no point to having it on. Just turn it off, turn off vsync, set the refresh rate to 144hz and just enjoy the low input lag.

[gamerscore]

What they said is true. You might wanna turn it off in an non optimized game for pc-- like Assassin's Creed Unity with too many people. Very ugly seeing them with almost double image effects. This is in BRR 120hz 1350vt with <40 fps.

To illustrate this effect...

[Chief Blur Buster]

If your display supports lower strobe rates, try a lower refresh rate.

If the game consistently runs at 75fps or 85fps or 100fps, and you're using a display that supports those strobe rates (e.g. BENQ Blur Reduction or ULMB), switch to a lower refresh rate. That eliminates the double-image effect. 75fps@75Hz strobed on a BENQ Z-Series, looks as crisp as 120fps@120Hz strobed. Same amount of zero-motion-blur, assuming you adjust persistence. This occurs when the motion is synchronized to the refresh rate (e.g. frame capping or VSYNC ON), for the same length of strobe flash per refresh cycle (milliseconds). For LightBoost, you're limited to 100Hz or 120Hz.

Look at http://www.testufo.com -- it looks just as clear at any refresh rate, as long as you've matched the strobe rate == refresh rate == frame rate. The limiting factor would be flicker (too low = too flickery) and increased stroboscopic effects (stepping effects during non-eye-tracking situations).

[gamerscore]

Thanks chief I appreciate the response. I'm using an AMD gpu the only options I can choose are 144hz, 120hz, 100hz, 60hz. I can't stand the rapid flickering @ 60hz, so I would like to use 75hz for less pronounced flickering. Can I try to set the refresh @ 75hz with Toasty's CRU if that is feasible with Benq BR? ACU @ low-medium settings I get 60~70 fps.

[Falkentyne]

Yeah you can make pretty much any refresh rate with CRU. Just make it as a custom refresh rate.
75hz is fine. You will probably need to enable 'single strobe' in the service menu (using the windows utility automatically enables single strobe) if you're at 75h or lower.

There's a list of refresh rates tested, ALSO with vertical total limits, in masterotaku's thread.
http://forums.blurbusters.com/viewtopic.php?f=13&t=560

if you' are using the pixel clock patcher, you may need to DISABLE it for 75hz or 85 hz or you will get a cable error, because I believe those lower refresh rates still use the single link limits, and if those get patched, you may get cable errors in the OSD, which you will not get if you don't use the pixel clock patcher. So keep that in mind, if you ever get "incorrect cable: please insert a dual link dvi cable" if you ever used the pixel clock patcher (for vertical total tweaks).

[gamerscore]

Yeah you can make pretty much any refresh rate with CRU. Just make it as a custom refresh rate.
75hz is fine. You will probably need to enable 'single strobe' in the service menu (using the windows utility automatically enables single strobe) if you're at 75h or lower.

There's a list of refresh rates tested, ALSO with vertical total limits, in masterotaku's thread.
viewtopic.php?f=13&t=560

if you' are using the pixel clock patcher, you may need to DISABLE it for 75hz or 85 hz or you will get a cable error, because I believe those lower refresh rates still use the single link limits, and if those get patched, you may get cable errors in the OSD, which you will not get if you don't use the pixel clock patcher. So keep that in mind, if you ever get "incorrect cable: please insert a dual link dvi cable" if you ever used the pixel clock patcher (for vertical total tweaks).

Thanks for the info falky. I'm new to this and want to make sure I'm not bricking my monitor by inputting crazy values

Are you sure you're not chief's alt account

[Falkentyne]

Huh, of course not.
if it weren't for chief, I would never have known about lightboost and blur reduction. It was his threads that got me to buy a VG248QE and use lightboost, after my Dell P1130 CRT finally got too broken to use, and then when the V2 firmware benqs were on the benq website store, I got one of those.

Almost everything I wrote was either found out by Chief, Masterotaku or Strobemaster ( http://display-corner.epfl.ch/index.php/BenQ_XL2411Z )

And um...you can't exactly BRICK the monitor.
The only real risk of damage to the backlight LED's is from using 120hz with vertical total tweaks at higher than 2.5ms (120hz is supposed to be rated up to 2.5ms maximum (the normal pulse width time is 0.08 ms (strobe duty 001 in the service menu; the windows utility goes down to 003 at far left slider), to 2.5 ms (030 in service menu/far right in windows utility). , which is how it usually is, but when you use the vertical total tweaks, instead of using the 120hz pulse widths, the monitor uses the *60hz* backlight pulse widths.
This is why the brightness increases slightly, because the pulse widths are longer. The problem is, the 60hz pulse widths go from 0.17ms (actually 0.167 ms) to 5ms. So you can use (strobe duty 030) up to 5 ms pulse width at 120hz, when 120hz is rated up to only 2.5ms maximum. So going past 2.5ms on the slider (strobe duty 016) drives the LEDs past their rated level, which could damage or shorten their lifetime! (this-backlight/led's "possibly" going out-hasn't been proven directly or tested for, but it's still common sense to take caution on). So care must be taken to not go past 2.5ms at 120hz or 3ms at 100hz.

this is explained in the display corner article by strobemaster.
http://display-corner.epfl.ch/index.php/BenQ_XL2411Z

BTW the Windows utility by Chief is calibrated based on 120hz and using the VT 1350 tweak (60hz pulse widths) which also apply for 100hz, so if you are NOT using the vertical total tweaks, you can use the chart on display-corner to see what the persistence range is without them.


Mode min [ms] max [ms]

LightBoost 100 Hz 1.88-3 ms
LightBoost 120 Hz 1.4-2.25 ms
MBR 60 Hz 0.17-5 ms
MBR 100 Hz 0.1-3 ms
MBR 120 Hz 0.08-2.5 ms
MBR 144 Hz 0.07-2.1 ms

Remember using vertical total tweaks makes the monitor use the 60hz pulse widths (which is the MS the windows utility shows and calibrated for (1350 vertical total), regardless of the refresh rate (you can't use VT tweaks at 144hz). So avoid going past 2.5ms at 120hz.

You would not want to do this with vertical total tweaks anyway (2ms is bright enough for most, and 1.0-1.5ms looks good), since when using VT tweaks, you want the strobe phase set to 000, and using 2.5ms or a high value (which increases the brightness) like that would put the crosstalk field close to the middle of the screen which you don't want anyway; the lower the persistence, the higher up the crosstalk field is (but the dimmer the screen).

The other "problem" is that 50hz single strobe doesn't work AT ALL unless you use VT tweaks (to force the monitor to use the 60hz pulse widths). The 50hz single strobe pulse widths don't work...the flicker is EXTREME and impossible to deal with if you "make" 50hz work by using a 1260 VT (this forces 60hz pulse widths), but at 50hz pulse widths (default with no VT tweaks), the screen fails to strobe at all, but the LED current is increased anyway, which causes over excessive brightness if your OSD brightness is set higher than 30%. Could cause the same damage or lowering the lifespan, sometimes the monitor will shut itself off and reset itself, sometimes it just goes out of sync and won't display anything. Double strobe at 50hz is fine, and I think that was intended. So only use strobing at 60hz, or if your video drivers add a 50hz mode, you can create a 50hz 1260 vertical total resolution in CRU to force 60hz pulse widths to avoid any accidental issues (this is only a problem in a few games which will FORCE 50hz at native resolution, e.g. Crysis and Crysis warhead/Crysis 2 are the only ones that do this silly thing).

[masterotaku]

The 50hz single strobe pulse widths don't work...the flicker is EXTREME and impossible to deal with if you "make" 50hz work by using a 1260 VT (this forces 60hz pulse widths)

I can use 50Hz with 1360VT. The problem is that low values of strobe phase (<=017 to be precise) activate the double strobe, so you have to go all the way and put strobe phase to 100. Crosstalk is at the bottom and doesn't completely disappear. Unless you want exactly 50Hz to synchronize some videos or emulated PAL games, I advise you to create a custom resolution of 51Hz (1502VT). Strobe phase still has to be higher than 017, but at 100 it has no crosstalk. And well, it has less input lag that way anyway .

(this is only a problem in a few games which will FORCE 50hz at native resolution, e.g. Crysis and Crysis warhead/Crysis 2 are the only ones that do this silly thing).

They don't exactly force 50Hz. They force the lowest refresh rate they find at the resolution you choose. The best trick is creating a custom resolution that only has the refresh rate you want, like 1920x1078@75Hz or whatever you want.