ATI HD5xxx series video cards do not support 120hz

[rcgldr]

If anyone is considering getting one of the newer 120hz monitor, note that the ATI HD5xxx series video cards max out at 85hz and will not support 120hz.

In addition, due to a quirk in these cards, if resolution is a multiple of 16x9, the mas refresh rate is 60hz.

 

[mactronix]

The new 10.5 Drivers include support for the 120 hz rate.

Mactronix

 

[rcgldr]

> The new 10.5 Drivers include support for the 120 hz rate.

Read the release notes, "support for 120hz displays on the ati radeon hd4000 series and ati radeon hd3000 series", not the hd5000 series.

Also although 120hz is new to LCD computer monitors, many CRT monitors can run at 120hz or faster (at lower resolutions), and video cards have supported those faster rates until the hd5000 series, which are apparently capped at 85hz, or 60hz if resolution is a multiple of 16:9.

 

[mactronix]

Ok fair enough my bad for not reading the release notes i guess.
Come on ATI get your act together. maybe they did this, locked it out of 120hz to stop people getting the 120hz flickering bug untill they can fix it ?

Mactronix

 

[rcgldr]

My guess is that ATI took a shortcut with the HD5xxx series video cards and didn't implement the faster refresh rates. Since CRTs run up to 200hz, and some HDTV's which can be used as monitors run at 120hz, I was surprised that ATI didn't anticipate that computer oriented LCD monitors would end up running at 120hz, and capped the HD5xxxx series to 85hz.

I'm also not sure why 16:9 resolutions are capped lower still at 60hz, which is really annoying on a CRT monitor (I use 16:9 on my CRT monitor when capturing video to be uploaded to youtube).

I bought and then returned a HD5870 video card because of this issue. I'm using an HD4870 which doesn't have either of these issues.

 

[amnotanoobie]

My guess is that ATI took a shortcut with the HD5xxx series video cards and didn't implement the faster refresh rates. Since CRTs run up to 200hz, and some HDTV's which can be used as monitors run at 120hz, I was surprised that ATI didn't anticipate that computer oriented LCD monitors would end up running at 120hz, and capped the HD5xxxx series to 85hz.

I'm also not sure why 16:9 resolutions are capped lower still at 60hz, which is really annoying on a CRT monitor (I use 16:9 on my CRT monitor when capturing video to be uploaded to youtube).

I bought and then returned a HD5870 video card because of this issue. I'm using an HD4870 which doesn't have either of these issues.

They probably didn't anticipate the trend towards 3D LCD's. This is probably also one of those features that they had to cut just to make production time.

 

[turnipfarmer]

The Catalyst driver may give you the option 120hz but the 58xx cards do support it - just create a custom monitor inf with the refresh rate you want forced.

My 16:9 DLP Projector works fine at 96hz and 120hz on a 5850.

 

[rcgldr]

The Catalyst driver may give you the option 120hz but the 58xx cards do support it - just create a custom monitor inf with the refresh rate you want forced.

I tried that before, and that simply removed all 16:9 resolutions as options. 1280x768, 1280x960, 1280x1024 were listed, but 1280x720 was removed from the list (along with all other 16:9 resolutions, 1600x900, 1920x1080) when I used a custom monitor.inf (using ResForce to set it).

My 16:9 DLP Projector works fine at 96hz and 120hz on a 5850.

That never worked for me, but I was using a HD5870 video card. ATI tech support previously confirmed the 16:9 resolution stuck at 60hz was a known problem.

 

[Ray Charles]

Concerned potential buyer of a gtx 470 or a HD 5850 but if the 5850 is capped at 85hz the its definately not futeristic and forget it then 470 all the way!!!!

 

[turnipfarmer]

The 5870 is no different (I'm actually using a 5870 BIOS); yes you will only have whatever res you force(can do multiple ones at once but haven't tried it), but you do always get the one you want unless the driver is created incorrectly.

If anyone wants an easy way to try and force 120hz on any setup (should work if it can read your registry EDID, can still do it if not but it's more of a bitch), give this a go (with the screen set to 60hz and whatever res you want to keep):

-Load Phoenix EDID Designer 1.3
(http://www.softsea.com/download/Phoenix-EDID-Designer.html)

-Extract Registry EDID
(Tools menu > select the listed option then click Extract EDID)

-Double the Pixel Clock
(click on the Detailed Timings tab, click the pencil icon to edit, type in double the whatever the current value is into the Pixel Clk field (round to 1 decimal place), click the disk icon to save the changes)

-Save the EDID
(don't forget to click the disk icon to save changes first, File menu > Save EDID As)

-Load Monitor Asset Manager 2.5
(http://www.entechtaiwan.com/files/moninfo.exe)

-Open the EDID you made
(File menu > Open and select the file you saved)

-Create a monitor driver
(File menu > Create INF, also check the res is correct in the right hand pane e.g. 1280x720 at 120Hz)

Now install the new driver, reboot and you should be able to select 120hz (set the res first, then go into advanced settings > monitor and set the refresh rate).

 

[turnipfarmer]

If this works but you get flickering or whatever on a 5xxx card, you prolly just need to up the idle clocks - try MSI Afterburner, or flash the cards BIOS.

 

[Ray Charles]

well this seems like a serious issue then the 470 is a better deal!

 

[rcgldr]

The 5870 ... if anyone wants an easy way to try and force 120hz ...

If it's just a case of tweaking software parameters, then why isn't this included as part of the Catalyst driver, and why do the release notes only mention the 3xxx and 4xxx series as being able to support 120hz rates?

 

[rcgldr]

not necessarily, you'll never know whats gonna happen with future drivers. Besides, is 120Hz that important?

I'm not sure in the case of 120hz lcd monitors, but the other issue with the 5xxx series is that all 16:9 resolutions are locked at 60hz, which is annoying on my CRT monitor. Although my CRT is 4:3, I use 1280x720 to capture videos for youtube, I see a stretched image during capture, but the final version is fine. With the 5xxx series locked 60hz, I get flicker and hourglass effect. The only widescreen CRT monitor I know of is the Sony FW900, 22.5" viewable, but that is a 16:10 monitor (1900x1200 85 hz recommended, 2304x1440 max).

I tried an HD5870, but the 60hz 16:9 was an issue so I returned that video card. I'm currently using a HD4870, which doesn't have this problem.