The highest resolution of the Vivitek DX977 is XGA (1024x768). That's 62% less resolution than a 1080p (1920x1080) projector, which is the most common resolution.
This projector's resolution (XGA (1024x768)) is in fact the worst resolution across all 15000:1 contrast ratio data projectors that were released around the same time as the DX977.
A WUXGA (1920x1200) native projector resolution is the best resolution amongst similar types of projector.
Data projectors with a higher resolution that might also be worth considering include the DH976-WT (£1,072.80) (1080p (1920x1080)), or the DU978-WT (WUXGA (1920x1200)) both from Vivitek or the Benq W2000w (1080p (1920x1080)).