VIP Problem with 85Hz Resolutions Frame Rate

Hi!

I am relatively new to Altera and Nios2 and I am now developping a system with an ArriaV which objective is to transform VGA signal in LVDS with the ADC TVP7002. For the moment I am able to detect and correctly display in a 1920x1200 resolution monitor a large number of 60Hz input resolutions, but when I try to display 85Hz resolutions I can not output it in a high resolution (max 1400x1050). On previous posts regarding the frame rate change I have read that the frame buffer is the IP responsible for this. I have my frame buffer with the recommended configuration and enough DDR3 memory:

http://www.alteraforum.com/forum/attachment.php?attachmentid=11829&stc=1

The IP chain of the system is:

cvi -> scaler -> frame buffer -> csc -> mixer -> cvo

Do you think I should focus on the Frame Buffer or is there any other IP I should check? :confused: Have you ever had a similar problem?

Thanks in advance!