Which is faster - 1080p or 720p source?

[engineerer]

I'm using Premier Elements 11 to prep some custom-sequenced Bluray discs, for strictly private use; and, I belong to various sites that offer good source material in either 1080 or 720 formats. My question is, which type of format should I grab and use, if my goal is to make the encoding and burning process faster?
Either format is good enough quality for my purposes; my REAL problem is all-too-frequent computer crashes, after long periods of encoding work, before anything gets stored on my HD in final form, ready to burn.
I realize that the working presumption is, since 1080 files are much bigger, they obviously will take longer. But, Premier doesn't and won't burn Bluray discs in 720P format; it only burns in 1080p format. So, for all I know, it might be faster and easier for it to:
(1) simply take any and all 1080 frames that are in my source, and put those quickly and easily into the corresponding time slots, on my videos;
-- rather than --
(2) have to generate an entirely new picture, in 1080 format, every time it encounters a frame or sample in 720 format.
Is there a known and reliable answer to this question?

[jagabo]

my REAL problem is all-too-frequent computer crashes, after long periods of encoding work, before anything gets stored on my HD in final form, ready to burn.

Fix your computer. That's the best solution. In all likelihood it's overheating. Add more cooling.

[drjtech]

If you have overclocked your CPU you may have overdone it. Otherwise I agree that you need more/better cooling.

[engineerer]

New info -
since I didn't get an answer, I tried it, using 1080 and 720 versions of exactly the same video source.
The 720p version (990 Mb) encoded slightly faster, at 27:52 min/sec.
The 1080p version (1.38 Gb) took 31:33.
Not enough difference to make any difference, by my standards . . .

[jagabo]

New info -
since I didn't get an answer, I tried it, using 1080 and 720 versions of exactly the same video source.
The 720p version (990 Mb) encoded slightly faster, at 27:52 min/sec.
The 1080p version (1.38 Gb) took 31:33.
Not enough difference to make any difference, by my standards . . .

You can't always count on that. Different codecs and different settings could cause the 720p version to take longer to decode.