I don't really get what you are on about. There is no "reference pixel" with a specific physical size. They can be as big as a fist or as small as a fraction of a mm.
A 1080p signal will be displayed on a 1440p monitor by interpolating the 'missing pixels'. A 1080p signal won't work on a 720p...
A laptop with a GTX 780m, GTX 880m, GTX 860m SLI, GTX 780m SLI, GTX 880m SLI, HD 8970M Crossfire or R9 M290X Crossfire and an Intel CPU with a QM suffix.
You are comparing an extreme editon i7 6 core with a midrange i5.
What about this?
It is true that it runs better on a 4 core i7 but is it worth it? Will Watch Dogs be the standard or an extreme exception?
If you have the cash go for a 6 core extreme i7.
Also Hyper Threading does not have to...
Lag? If it is like load stutter then maybe more RAM may help the situation (Watch Dogs is known to stutter on higher settings). If the framerate is low then your graphics card is too weak. Lower you settings to 'low' and disable AA. Maybe turn down resolution.
Exact motherboard model needed.
The 865P chipset only supports the Pentium 4. The 865PE supports the dual-core Pentium D. Be aware that the Pentium D is weak by today's standard.
No support for C2D.
Download GPUZ. Open it. Press the small question mark next to "Bus Interface" then "start render test" then take note what it says in "Bus Interface". It should say PCI-E 3.0 x16 @ x16 3.0.