120hz HDTV vs 60hz HDTV (both 1080p) using GTX 275

toofly

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Jul 27, 2009
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I've got a question for anyone with an answer...
I'm considering buying a TV for my monitor but had a couple questions about effectiveness.

I'm looking at two different TV's but for the most part the main difference is the refresh rate and with the lower refresh rate, a larger size. Both TVs are 1920x1080.

I know that the refresh rate is the number of times a single frame will be displayed each second. So for example the standard 30fps of Television programing will divide evenly into either refresh rates with an even number of frames, however the film/movie standard of 24fps divides unevenly into 60hz and therefore requires the 2:3 pull down algorithm. That issue is eliminated with 120hz refresh rate as 24fps divides evenly into 120hz, HOWEVER, =( I also am into gaming...
My Rig:

CoolerMaster 932 Case
Gigabyte EX58-UD5 MoBo
i7 920
12gb OCZ XMP Ready DDR3 1600
EVGA GTX 275 896MB HDCP Ready
CORSAIR CMPSU-750TX
CoolerMaster V8

So i'm slightly worried about frame tearing, but that shouldn't be an issue with 120hz right? (as I doubt anything i play (MW2) will be displaying/out pacing 120fps...)

So your thinking, "why is this guy even asking, just go for the 120hz..."

My question is, my GTX275 has two DVI outs, no HDMI. So I'm looking at getting...
http://www.newegg.com/Product/Product.aspx?Item=N82E16812622014&cm_re=hdmi_to_dvi-_-12-622-014-_-Product
but the product description says "supports players/tv up to 60hz"
or...
http://www.newegg.com/Product/ProductReview.aspx?Item=N82E16812105013
But i don't know if I will have the same issue.

My question is:
Does anyone know if it is even possible to go from DVI to HDMI and push 120hz? Because if not, then am I SOL with my 275?

I want the TV for normal television viewing through Direct TV, Blu-ray playback from my PC, AND frequently play video games off of my system.


 
Solution
More or less 120Hz HDTV adds frames in 120Hz mode. Playing games in 120Hz will induce additional input lag due to the fact that the added frames must be created by the HTDV. It takes a little time to do so, thus additional input lag.

Most HDTVs should have "Game Mode" which sets the refresh rate to 60Hz, other you will need to do so manually.

toofly

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Yeah I read a few places saying that a lot of the 120hz TVs were just adding frames on the TV's end, but I've also read (haven't seen) people talk about fast paced action scenes on 60hz looking slightly choppy.

The TV in question is:
http://www.costco.com/Browse/Product.aspx?Prodid=11492759&whse=BC&Ne=5000135+4000000&eCat=BC|79|2341&N=4001374%204294899203&Mo=9&No=2&Nr=P_CatalogName:BC&Ns=P_Price|1||P_SignDesc1&lang=en-US&Sp=C&topnav=
 
well between gaming and BD movies, i haven't seen it (i have a 37" vizio 60Hz)

and like i said for gaming, you would still only get 60fps (with extra frames made from ones around it), also this interpolating can induce some latency since it needs to calculate the interpolated frames
 
More or less 120Hz HDTV adds frames in 120Hz mode. Playing games in 120Hz will induce additional input lag due to the fact that the added frames must be created by the HTDV. It takes a little time to do so, thus additional input lag.

Most HDTVs should have "Game Mode" which sets the refresh rate to 60Hz, other you will need to do so manually.
 
Solution
I'm not sure about how the TV handles it, but on the gaming end, extra frames are not just created by the HTDV. They are just left in memory until the video card updates it. You'd likely want to turn on V-sync at all times, and should eliminate any tearing and allows for higher than normal frame rates while V-sync is active.

If you are wondering, the monitor just displays a block of memory every time it refreshes. When a video game wants to update a frame, it just changes that same block of memory, and then the monitor will display what the memory has in it. V-sync just locks that memory while the monitor updates it's image, so the video card can only update that block of memory between refreshes, which prevents tearing. If that block of memory is not updated between refreshes, it just redisplays that same block of memory, and be the same as before the refresh.

I could see potential issues at 120Hz, due to limiting the time V-sync has to allow an update to the image, or tearing issues if off, but having never used one, I don't know.

I bet it would look awesome on a game that your system could do more than 120 fps.