Anyone using 4850 with 2 monitors?

T

TheKing

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Jun 26, 2007
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I'm having problem with an ATI 4850 and dual monitors setup. When I use the Catalyst Control Panel to overclock the card even for 5MHz, the sytem will crash under a dual montior configuration. I can overclock fine if I only connect 1 monitor. If anyone using a 4850 with dual monitor setup, pls help to test if you can overclock using Catalyst 8.8 or 8.9 version. Thanks!
 
Is it possible having the 2nd monitor hooked up is causing it to work just hard enough to overheat it? Have you adjusted the fan yet?
 
I am, i have my Visiontek 4850 hooked up to a Westy (1920x1080) and a 2005FPW (1680x1050) both using DVI.


i ran ATI's auto-tune function and it seemed to OC fine.. although i never ran it at those speeds..

i think it detected something like 680 core or something like that..

but no crash when it was goign through those OC steps..



When you say crash are you talking about a hard reboot? BSOD? driver failure?



have you tried each monitor seperately to ensure it isn't one of the DVI ports?
 
veedubfreak said:
Is it possible having the 2nd monitor hooked up is causing it to work just hard enough to overheat it? Have you adjusted the fan yet?
Click to expand...

I don't think it's overheating. I'm using an aftermarket heatsink and load temp is only 55C. Also, overclocking from 625 to 630MHz isn't much at all. If I only use a single DVI port, I can overclock over 700MHz without any issues.



H-street said:
I am, i have my Visiontek 4850 hooked up to a Westy (1920x1080) and a 2005FPW (1680x1050) both using DVI.


i ran ATI's auto-tune function and it seemed to OC fine.. although i never ran it at those speeds..

i think it detected something like 680 core or something like that..

but no crash when it was goign through those OC steps..


When you say crash are you talking about a hard reboot? BSOD? driver failure?


have you tried each monitor seperately to ensure it isn't one of the DVI ports?
Click to expand...



H-street, thanks a lot for helping to test. When I set anything above 625MHz and hit "Test Custom Clocks", the screen will flash a few seconds. Then, the PC reboots itself. BTW, I've tested this with Catalyst driver 8.8 & 8.9 with Vista 32 and Vista 64 and even fresh reinstall of Windows. All having the same problem. However, the strange thing is it works perfectly fine with a single port. It also works in dual monitor modes when I use other software to overclock, such as AMD CPU Clock Tool & ATI Tray Tool. The only problem is overclocking with Catalyst in dual monitors mode. First I thought it's a bug in Catalyst, but it works for you, so I just don't know what are the possible causes.

I also tested each DVI port independantly, it works as long as a single monitor is connected.
 
Sounds like you are hitting that magic number where the video card bumps the clocks. Video cards overclock in steps, so you could be hitting the point where theres not enough voltage to support the overclock anymore and cause the reboot.
 
This is getting rare. I called my dealer and told him about the problem of my 4850. He told me he had reproduced the exact same problem with other 4850s (Powercolor, ATI & Gigabyte) and he said that this is ATI driver bug. He told me not to send the card to him for replacement and all ATI 4850s exhibit the same overclocking problem with dual monitors attached. I don't know if he just said this to make me not returning the card. If this is a well known and wildspread problem, more people should have encountered it. Anyone else with dual montiors want to test and confirm? Thanks!
 
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