S27A950 / HD4850 slow desktop windows issue

Solar AU

Honorable
Aug 10, 2012
28
0
10,540
Hi all,

spend many hours trying to fix the below without success. Would really appreciate if anyone could help or has an idea what is causing the below.
Thx & rgds!!

TLDR version
I see lots of lag / stutter/ screen tearing / low “refresh rate” (image below) on my new Samsung S27A920 120Hz monitor. GPU is HD 4850. This only seems to happen for “overlapping” windows on the desktop.


Long version
Could you pls help with the below.

- I use Vista 64bit home edition, CPU is 2.66GHz Intel Core i7 920, 6GB ram
- bought a new Samsung 120Hz display S27A950
- DVI-I dual link cable used (was included with the monitor)
- removed all drivers for my screen(s) and the GPU drivers for my ATI HD 4850 (using Driver Sweeper, Catalyst Install manager->uninstall), removing all ATI entries in C:\windows\assembly and un-install from device manager)
- connected the screen (DVI port / cable) and installed ATI Catalyst 12.6
- configured the screens with the latest drivers / profiles

That worked all ok. Catalyst works. The correct screen names show in the Display Settings. I can set 120Hz on the monitor. And also the monitor menu (activated via the buttons on the monitor) confirms 120 Hz. Image of driver config at end of this post.

I am fairly confident the screen runs at 120Hz, bc “Fraps” showed me fps between 80 and 100 on a game I tested and the game runs smooth.
Everything else runs smooth as well except when windows overlap (!!) on my desktop (see image below). I don’t see this effect on the desktop background. Mouse and windows move very smooth on the background.

I have tried all the below, but the effect is all the same
- Single-screen or dual screen connected
- tried both DVI ports of the GPU
- 60Hz / 120 Hz
- Various settings combination in catalyst re “screen scaling” / GPU scaling on / off etc

Not tried yet – but will check tonight
- Compare the effect if I only connect my other screen (23in Dell)
- Compare the effect if I connect the Samsung to another computer


effect image: overlapping window lag on desktop
i-4vhKXQ2-L.jpg

in case you cant seethe image, here is the link
http://www.thorsten-rust.com/photos/i-4vhKXQ2/0/L/i-4vhKXQ2-L.jpg

Driver config
i-t4q8Smr-L.jpg

in case you cant see the image, here is the link
http://www.thorsten-rust.com/photos/i-t4q8Smr/0/L/i-t4q8Smr-L.jpg
 

Solar AU

Honorable
Aug 10, 2012
28
0
10,540


many suggestions here: http://www.tomshardware.com/forum/259371-33-windows-trail-moving
Thx!!!

this worked for me

Control Panel
System
'Advanced' tab
'Performance': 'Settings' button
Click on 'Custom' radio button
unselect 'Show window contents while dragging'
Apply
OK