I have a Dell XPS running a Radeon HD 5450 (http://www.amd.com/en-us/products/graphics/desktop/5000/5450 ). I recently purchased a Dell U2515H (http://www1.la.dell.com/vc/en/corp/peripherals/dell-u2515h-monitor/pd.aspx?refid=dell-u2515h-monitor&s=corp) and a DVI to HDMI cable (https://www.amazon.com/gp/product/B014I8UXKG/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1) hoping to get 2560 x 1440 resolution. As best I can tell, the DVI output on the card, the cable, and the monitor are all rated for it. As it sits the best I'm able to obtain is 2048 x 1152. Is there any solution to this besides replace monitor/graphics card?
The similar adapters have max resolution 1920x1200 ( the same bandwidth is required for 2048x1152)
I think it is an answer. Your DVI to HDMI adapter cannot support 2560 x 1440 resolution.