Olly has already sold more than 1D iirc. (in the UK only of course, and I'm talking about their latest album).

One Direction - 155,000 (total: 220k+, worldwide first week 1m+)
Olly Murs - 127,000
Little Mix - 53,000 (total: (90k)
JLS - 36,000 (75k)
Leona Lewis - 27,000 (60k)

Susan Boyle - 36,000 (60k)
Jonathan & Charlotte - 25,200 (total: 90-100k)

Good stuff from 1D and Olly, 1D's worldwide performance has been particularly impressive. The jury is still out on Little Mix, they've sold about 500,000 singles which helps.

Not good at all for Leona and JLS not doing much better. SuBo probably won't make it to 1m worldwide with this album.

Other To Date Figures:
Steve Brookstein - Heart & Soul - 105,080
Steve Brookstein - 40,000 Things - 3,632

Joe McElderry - Wide Awake - 103,471
Joe McElderry - Classic - 247,060

Olly Murs - Olly Murs - 760,598
Olly Murs - In Case You Didn't Know - 880,944

Alexandra Burke - Overcome - 816,324
Alexandra Burke - Heartbreak on Hold - 15,592

(All figures from Music Week)

One Direction Worldwide Sales To Date: (more than) 5,221,000

Some of those are from 2011 of course but their 2012 sales total will be in excess of 5m which will be the highest number of albums sold by an X Factor act in one calendar year.

I like her, but I doubt that. 1D are off to a good start with their 2nd album.