Radeon 4850 second monitor flickers when overclocked

[ss284]

Using the catalyst 8.6 drivers, my second monitor has weird flickering every few seconds when I'm overclocking using CCC. Even a 5mhz overclock will cause it, is anyone else experiencing the same problems?

-Steve

 

[Sylvanas]

Originally posted by: ss284
Using the catalyst 8.6 drivers, my second monitor has weird flickering every few seconds when I'm overclocking using CCC. Even a 5mhz overclock will cause it, is anyone else experiencing the same problems?

-Steve

Try the new 4xxx hotfix driver here

 

[ss284]

I'll give that a shot, thanks.

 

[ss284]

Its still flickering with the hotfix drivers. Anyone else experiencing this issue(or not)?

-Steve

 

[Sylvanas]

What are you're case temps? Check the DVI connection is secure

 

[ss284]

Case temps are 32C and the card loads at 80-85C. DVI connection is fine, it only occurs when overclocking with CCC, no matter how small the overclock.

 

[Sylvanas]

Does it occur if you OC with another application e.g. Rivatuner?

 

[ss284]

Rivatuner doesnt support the 4850, at least not yet.

 

[ss284]

Bump, someone out there must be using a 4850 with two monitors.

 

[Dman877]

If you switch dvi ports, does the problem stay with the same port? It may just have a bad ramdac...

 

[ss284]

Dman, I tried that out and it indeed looks like the ramdac on monitor 2 is the culprit. Whats strange is that it only appears when overclocking. Now I'll have to take it best buy and hope they still have stock.

Thanks
-Steve

 

[ss284]

I'm using DVI though, so shouldn't the DAC have no effect on the signal?

 

[ss284]

Someone over at rage3d has the same problem, a visiontek 4850 with a flickering second DVI port while overclocking. this leads me to believe it might not be a problem with just my card. Someone on these forums must have a 4850 running dual monitors that can do a simple overclocking test to see whats happening.

 

[Pollock]

I just installed my 4850 last night, running dual monitors. I have to say I'm not experiencing what you're describing, with 8.6 + hotfix and overclocked to 690/1138.

My second monitor is VGA, though, so I don't know if that could cause a difference?

 

[kmmatney]

Originally posted by: Pollock
I just installed my 4850 last night, running dual monitors. I have to say I'm not experiencing what you're describing, with 8.6 + hotfix and overclocked to 690/1138.

My second monitor is VGA, though, so I don't know if that could cause a difference?

That was going to be my suggestion - try using a VGA adapter on the second card. Not a real solution, but it would be interesting to see if the flickering goes away.

 

[ss284]

VGA seems to fix the problem. No flickering while using VGA, although I will test further. It looks like an issue with the DVI controller/circuitry on the second port.


Edit: Nevermind, the problem is still there even with the DVI to VGA adapter. Pollock, is your second monitor an LCD? If so, what refresh rate do you have it set at?

 

[kmmatney]

I had a problem with my 2900Pro and my LCD. Every few seconds the screen would black out, and then come back on. I don't know if this is what you are seeing on yours. I went to the digital panel options in CCC and played with the settings "Reduce DVI frequency on High-res displays" and "Alternate DVI operational mode". I checked both settings and the problem went away. Then I unchecked the settings and the problem was still gone, and has never came back (been 6 months so far).

 

[ChronoReverse]

Hmm, it looks like mine is doing that too (overclocked). It's a weird flickering that occurs sometimes when an Aero effect is used (like the minimize animation). Nothing like this ever happened with my 3850.

While probably a driver bug, I hope this is fixed soon.

 

[JBT]

Mine does the same thing when OCed. I also posted in the rage3d thread.

Both my Dells a 2405 (primary) and 2007 (secondary) are at 60hz. The secondary will flicker. Its pretty annoying... I'm thinking of taking it back but I just shipped off my older 8800GT... arrr

 

[ss284]

I'm hoping its a driver thing, but my gut feeling is that its a hardware issue that has something to do with powerplay and the clock ic.

 

[ChronoReverse]

From more testing I'm quite sure it's a driver thing.

UNDERCLOCKING even one notch causes the same kinds of flickers. Yet when PowerPlay drops the frequency to 160MHz (and 500MHz before I updated the BIOS), there's no such flickering.