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Force 4k LED to go from 30 to 60Hz

cloudnoize

cloudnoize

macrumors member
Original poster
Aug 15, 2015
51
2
Burbank, CA
Hey guys,

I was recently given a Seiki SE39UY04-1 LED TV and have it plugged into a Mac Pro (upgraded to 5,1 from 4,1 with 12 cores, originally 8). I'm running Sierra.

My graphics card is a GTX 660. The Seiki does not have Display Ports (only HDMI) so what I did was purchase a Display Port 1.2 to HDMI 2.0 Ultra HD 4K Active Adapter and connected a HDMI 2.0 cable to it.

Upon booting, the Seiki still says 3840-2160 @ 30Hz. I was hoping just maybe this would do it but it doesn't. Any of you guys have had success in getting this to work? Everything but the mouse lag is quite nice. I'd just like the lagging to be less.

Thanks!
 
Sorry, you can't do 4k@60 over HDMI with your video card. That's a very common misconception, the DP->HDMI adapter just makes the port work in HDMI mode, and the best that card can do is HDMI 1.4, which supports 4k only at 30 Hz.
You have to change either your monitor (with one with DP 1.2 input) or your video card (with one with HDMI 2.0 output).

EDIT ok I just saw you said "active" adapter. In theory that should work, but these things are often problematic with some combinations. Guess you're on the unlucky side :(
 
Last edited:
biffuz said:
Sorry, you can't do 4k@60 over HDMI with your video card. That's a very common misconception, the DP->HDMI adapter just makes the port work in HDMI mode, and the best that card can do is HDMI 1.4, which supports 4k only at 30 Hz.
You have to change either your monitor (with one with DP 1.2 input) or your video card (with one with HDMI 2.0 output).

EDIT ok I just saw you said "active" adapter. In theory that should work, but these things are often problematic with some combinations. Guess you're on the unlucky side :(
Click to expand...

Thanks for the quick response, biffuz. Appreciate it. Do you think an app like SwitchResX or even NVIDIA's WebDriver can do what I'm after or am I'm still stuck because of the video card not being 2.0 output? I do agree that's it's hit or miss. I've seen people in my situation that have gotten this to work and probably due to different combinations.
 
It was occasionally "possible" with the GTX 680 for Mac with active adapter using the NVIDIA web driver and SwitchResX, but was not always reliable at 60hz. Needed to disable all image processing on the monitor's menu settings (this was a Samsung 4K HDTV monitor) and would have to reboot several times to get it to work correctly with the adapter. Often would be working and suddenly would drop back to 30hz after a black flash on the monitor. Happened a few times when changing between Adobe applications (that use Mercury Transmit for previews) and that was semi-understandable, but also happened randomly with other applications. Sometimes hot disconnecting the adapter with HDMI still connected would help, other times the monitor would not even get a signal back unless display output settings were changed. Truthfully it was more trouble than it was worth.

For my needs, I ended up setting that monitor output 1920x1080@60hz -OR- 3840x2160@30hz depending on the work I was doing. It is mostly used as a preview monitor for video work and 90% of the time 1920x1080@60hz is fine. When working on designs in AE, I sometimes bump up to 4K/UHD. Was looking into a large wall-mountable native DisplayPort monitor awhile back, but that money was better spent elsewhere.
 
What you are trying to do should work. The 660 is capable of outputting 4K/60 from the DisplayPort, but not the HDMI ports, which will max out at 30Hz. Even if the 660 were capable of outputting HDMI 2.0, it wouldn't matter since Apple does not support 4K/60 over HDMI anyway.

One problem with using TVs as monitors is that many TVs only have a certain number of HDMI ports that are actually 60Hz-capable. I am using a Samsung 40" 4K TV as a monitor. It has 3 HDMI inputs that each support full 4K/60. My Vizio 4K TV in the living room has (I think) 4 HDMI ports, but only one of them is 60Hz capable.

On my machine, that I'm typing this from, I have a GTX 1080. I'm using an active DP adapter to output to the TV's HDMI 2.0 port. Again, the reason for that is that Apple doesn't support HDMI 2.0 directly, so even if I plug an HDMI 2.0 cable into the HDMI 2.0 port on my video card and run it to the HDMI 2.0 port on my TV, I get 30Hz max output.

Anyway, check your TV's port situation.
[doublepost=1522245914][/doublepost]Somehow I didn't notice that you put the actual model number of the TV in your question. I just Googled it, and it looks like the TV itself doesn't do 4K/60, since it has only HDMI 1.4 ports.

So, you're converting from DP -> HDMI 2.0 -> HDMI 1.4 and the end result can only be 4K/30Hz.
 
Agree that this TB only has HDMI 1.4 input. So impossible to get 4k 60Hz. That 120Hz is the monitor refresh rate, nothing to do with the input standard.
 
cloudnoize said:
I was recently given a Seiki SE39UY04-1 LED TV
Click to expand...

That is a discontinued model that only supports 4K at 30Hz. It has nothing to do with your Mac, video card, MacOS, cable, etc. Early Seiki 4K TVs were enormously cheaper than all other 4K displays out there, but they cut a lot of corners with things like subpar refresh rates and chroma.
 
Thank you all for the info, guys. Excellent stuff! I was afraid I wouldn't be able to do this. I thought that maybe with today's technology, cables, etc, I may be able to force the monitor to do such things.

@Mockletoy You mentioned having 4K TV with 60Hz capability. With my current graphics card, adapters, cables, if I got a 4K/60, will I then be able to get 60Hz? Thx.
 
Look into SwitchResX software. I needed to use this to get 60Hz from my rig using DP>HDMI Active Adaptor from AMD RX460 under Sierra. If your TV will support 60Hz 4k, you should be able to make it happen. Also, look into whether "gaming mode" is available on your TV; my Samsung has such a mode, and using it dramatically reduces screen lag.
 
DPUser said:
Look into SwitchResX software. I needed to use this to get 60Hz from my rig using DP>HDMI Active Adaptor from AMD RX460 under Sierra. If your TV will support 60Hz 4k, you should be able to make it happen. Also, look into whether "gaming mode" is available on your TV; my Samsung has such a mode, and using it dramatically reduces screen lag.
Click to expand...

I do have SwitchResX and it's a great app and the TV does support 60hz but only at 1080p. Anything higher and I just get a blank screen. Also, no gaming mode. Thx.
[doublepost=1522361396][/doublepost]
CapnDavey said:
I think there is info on the Seiki website for doing this mine does the same thing
Click to expand...

I have found little to no info on the Seiki site... not even on discontinued models which I find strange.
 
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