120hz on Intel HD4000?

Cythx · 27 May 2012 at 20:41

I cannot see the option for 120hz on the Intel Graphcis Control Panel.

I am using a HDMI connection to a 120hz monitor, does Intel's HD4000 not support 120hz?

Lunawolfy · 27 May 2012 at 20:43

I can't imagine a game, or resolution in which it could drive, successfully @120Hz

Although I may be wrong.

Cythx · 27 May 2012 at 20:45

Not playing games atm, would just prefer running the monitor at 120hz rather than 60hz and wondering why I can't.

Sin_Chase · 27 May 2012 at 21:07

HDMI does not have enough bandwidth for 120Hz at higher resolutions. You need to use DVI-D or Displayport.

Cythx · 27 May 2012 at 21:22

Thanks

Surveyor · 27 May 2012 at 21:40

Sin_Chase said:
You need to use DVI-D or Displayport.

Dual link DVI for 120Hz.

A lot of motherboards (I won't say all as I haven't checked) only provide a single link DVI.

As a case in point the Gigabyte GA-Z77X-D3H's DVI is only single link.

It also doesn't have a DisplayPort output.

Sin_Chase · 27 May 2012 at 22:15

Quite right on the Dual Link requirement.

Kinda screwed in that case! Expansion card required.

Surveyor · 27 May 2012 at 22:25

Sin_Chase said:
Quite right on the Dual Link requirement.

Kinda screwed in that case! Expansion card required.

I've assumed it's the motherboard in his sig.

But then he's got two GTX 670s in there as well.

If it isn't he'll have to let us know and we can check.

Cleeecooo · 27 May 2012 at 22:27

Surveyor said:
I've assumed it's the motherboard in his sig.

But then he's got two GTX 670s in there as well.

If it isn't he'll have to let us know and we can check.

I'd presume it wasn't as nobody would use onboard when they have 670 SLI

Sin_Chase · 27 May 2012 at 22:28

Cleeecooo said:
I'd presume it wasn't as nobody would use onboard when they have 670 SLI

He did mention the HD4000 which is an onbaord chip though.

Anything connected to that will be limited by it irrespective of his expansion cards. Either the expansions cards are not in or there is a reason he needs to use the ouput from the HD4000.

james.miller · 27 May 2012 at 23:01

I dont know why HDMI doesnt support 1920x1080/120hz but it certainly isnt down to bandwidth - it has more than enough. Perhaps there's a limit on the refresh rate that HDMI supports. To give you an idea, 1920x1080/120hz requires roughly 20% less bandwidth than the 2560x1600/75hz (24bit colour) that hdmi 1.3 officially supports.

2560x1600 = 4,096,000 pixels per frame * 75 = 307,200,000 pixels per second
1920x1080 = 2,073,600 pixels per frame * 120 = 248,832,000 pixels per second.

Sin_Chase · 27 May 2012 at 23:27

Most PC users use 32Bit colour.

james.miller · 28 May 2012 at 18:10

The 32bit that PC's use is actually 24bit + 8bit for the alpha channel (transparencies). Not sure if its true any more but in the beginning 32bit was needed for gpus to display transparencies correctly. What is sent to the display, however, is 24bit or 8bit for each color channel.

30 bit is the next real step up (10 bit per channel) and modern gpus do support it (and even higher) however not many displays do.