What video card are you using? Going from 1280x1024 resolution to 1920x1080 is a big jump in GPU processing requirements.
Do you know which company actually makes the AriaNet monitor? LG is a known major player in LCD monitors but Im not familiar with that model.
(fixing your links)Arianet 2362WD 23 £117LG W2253TQ-PF 22" £131