Please note that the signal from your PC has much higher resolution than SD video format resolution.
The PC input signal will pass through the scan converter on VR-5 and VR-3 and it will be down-converted to SD format. Usually, pictures look good even after the down-scaling, but small texts may look blurry on the unit. This is normal on VR-3 and VR-5 as they support SD format only.
To avoid this, please use larger font-size and try different fonts.
Thanks!