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GTX 480 maxes out at 1920X1080 over HDMI port

GeezerMan

Platinum Member
Jan 28, 2005
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I'm testing out my new Auria EQ276W 27" 2560X1440 monitor this week with my Evga GTX 480. It will only display a max of 1920X1080 using the mini HDMI port, that uses a supplied mini to full size HDMI cable.

Using the DVI ports, and dual link DVI cables, I get the full resolution.

Now, I also tried using an old AMD DVI to HDMI adapter, and I get full resolution with the HDMI cable. I'm using the same HDMI cable to test these ports.

Shouldn't the HDMI port also display 2560X1440? I've seen plenty of aruments on the web of limited bandwidth with HDMI, but my understanding is HDMI is fine for 2560x1440.

I can use the DVI to HDMI adapter if I must, unless there is some performance loss by doing so. I would prefer to use just a straight HDMI all the way, but it looks like it can't do it even though Evga says it's a HDMI 1.3 version.

I'm thinking of a scenario where the monitor tells the card via HDMI and EDID that it's max resolution is 1920X1080 because the manufacturer has not rated the HDMI as version 1.3. But when using a DVI to HDMI adapter , the EDID info does not get relayed correctly.



Any ideas on this?
 
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jacktesterson

Diamond Member
Sep 28, 2001
5,493
3
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I'm not aware of any video card that currently supports 2560x1440 over HDMI.

It may be theoretically possible, but its not an active feature that I'm aware of with any card.
 

bunnyfubbles

Lifer
Sep 3, 2001
12,248
3
0
both the HDMI out on the video card and the HDMI in on the monitor have to support such a resolution beyond 1080p for it to work, one or both are a weak link, my bet is the monitor definitely does not support resolution beyond 1080p over HDMI, my Dell U2711 has such a limitation and thus I have to use dual link DVI or DisplayPort to get 1440p.

That being said, there really isn't much reason to use HDMI other than it is easier to plug/unplug, unless you want to send audio to your monitor...which, while that monitor does have speakers, I imagine they sound awful, so not even then...
 

ViRGE

Elite Member, Moderator Emeritus
Oct 9, 1999
31,516
165
106
I'm not aware of any video card that currently supports 2560x1440 over HDMI.
Both the card and the monitor would need to support the so-called "FastHDMI" functionality. The Radeon HD 7000 series and GeForce GTX 600 series introduce this support, however it's not present on any PC monitors currently shipping. The HDMI ports on those 27" IPS monitors are really for easily hooking up 1080p devices that only offer HDMI output (A/V equipment and the like).
 
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GeezerMan

Platinum Member
Jan 28, 2005
2,096
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Interesting. It does transmit 2560X1440 by using an old AMD DVI to HDMI adapter at the card with the HDMI cable to the HDMI port on the monitor. I get sound too. There are some other guys that are getting 2560X1440 by using HDMI direct from the card to this monitor.
Part of my question is curiousity, though I could use the onboard speakers every now and then.

This is the adapter I'm talking about;
http://www.microcenter.com/product/305974/DVI_to_HDMI_Adapter_for_ATI_Radeon_HD_4000_and_3000_Series_Video_Cards?gclid=CMSJ6tCW0bMCFUqoPAodxzgAdg
 
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ViRGE

Elite Member, Moderator Emeritus
Oct 9, 1999
31,516
165
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Interesting. It does transmit 2560X1440 by using an old AMD DVI to HDMI adapter at the card with the HDMI cable. There are some other guys that are getting 2560X1440 by using HDMI direct from the card to this monitor.
Part of my question is curiousity, though I could use the onboard speakers every now and then.

This is the adapter I'm talking about;
http://www.microcenter.com/product/305974/DVI_to_HDMI_Adapter_for_ATI_Radeon_HD_4000_and_3000_Series_Video_Cards?gclid=CMSJ6tCW0bMCFUqoPAodxzgAdg
HDMI is just SL-DVI with a different pin arrangement. There's nothing that adapter does that an HDMI wouldn't already do.
 

GeezerMan

Platinum Member
Jan 28, 2005
2,096
3
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HDMI is just SL-DVI with a different pin arrangement. There's nothing that adapter does that an HDMI wouldn't already do.

OK, so as long as the cable can handle the bandwidth of 2560X1440, and as long as the monitor can handle it too through the HDMI port, then it's all good? It could be possible that Auria has not officially rated the HDMI port as able to handle the bandwidth.
 

ViRGE

Elite Member, Moderator Emeritus
Oct 9, 1999
31,516
165
106
It could be possible that Auria has not officially rated the HDMI port as able to handle the bandwidth.
That's exactly it. When they needed to increase the amount of bandwidth available via HDMI, the HDMI forum merely increased the clockspeed of the connection from 165MHz to 340MHz (this is where the "fast" in FastHDMI comes from). However controllers that can sink FastHDMI are almost unheard of. Case in point, the controllers on these Korean monitors are not spec'd to handle FastHDMI, hence they don't officially support it. When you hear about people getting 2560 to work, what they're doing is basically overclocking their monitor's display controller.
 
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GeezerMan

Platinum Member
Jan 28, 2005
2,096
3
81
That's exactly it. When they needed to increase the amount of bandwidth available via HDMI, the HDMI forum merely increased the clockspeed of the connection from 165MHz to 340MHz (this is where the "fast" in FastHDMI comes from). However controllers that can accept sink FastHDMI are almost unheard of. Case in point, the controllers on these Korean monitors are not spec'd to handle FastHDMI, hence they don't officially support it. When you hear about people getting 2560 to work, what they're doing is basically overclocking their monitor's display controller.
I'm a little hazy on resolution and refresh rate and which portion does what to to bandwidth, an increased resolution will increase the amount of info sent, so higher bandwidth used, tack on a higher refresh rate and it increases bandwidth too, then tack on 3D and more bandwidth.

Could be that you could overload the HDMI port on the monitor, since it's not rated for it, when using 2560X1440 with gaming and audio too?

Using the DVI to HDMI adapter and HDMI port on the monitor, I get the 2560X1440, and it says it's refresh rate is 60 Hz, so it's not overclocking the refresh rate.

If it does overclock using HDMI, then I'm probably better off using the DVI for better reliablity and less stress.
 
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