I have a 1080p LCD TV with a refresh rate of 60 Hz. My graphics card has a HDMI output, if I use this TV as a monitor will I notice any loss of quality compared to a purpose built computer monitor?
It is difficult to answer this question, because you provided us with almost no information. TV tells us almost nothing and purpose built monitor tells us almost nothing. If you tell us model of your TV someone may have an idea how good it works. You also need a reference monitor to compare it to. Some monitors are great and some are awful.
Usually, TVs are optimized for viewing from distance and they have higher dot pitch, meaning that pixels are less densely packed on the screen itself.
On the other hand, monitors are usually smaller and have lower dot pitch and are optimized for viewing at shorter range.
The only way to know for sure it to compare your TV with a monitor. Some TVs may look great, while others could produce "CAN'T UNSEE" effect.
I have a 32" Samsung 1080p that works great as a monitor when I'm sitting in my comfy chair with some 2-3m between me and the TV.
However I have seen other TV:s that is totally worthless for this purpose.
I've done it without complaint, but like they say, it just depends. If it doesn't look sharp enough for you, a device like these: http://www.atlona.com/Atlona-Pal-HDMI-to-NTSC-HDMI-Converter-1080p.html can help.
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