atx = 12 x 9.6 >< e-atx = 12 x 10.7 --> approx. 1.1" wider
your stock mthrbrd is fixed to a mthrbrd tray (tempan), any new mthrbrd will need fixed to same tray, holes (stand-offs) will need to line up. Any tray stand-offs that do not line up would need to be insulated. By the looks of it, you'd lose your black cable organizer, it'd need two new screw holes drilled into tray, moved over 1.1" etc.(industrial velcro, if no access to a drill w/metal bit as a temp solution). Your best bet is to buy your new MB from a source who'll accept returns, in the event the e-atx fails to mate to your mthrbrd tray, or available wall space.
you should search for a visual atx vs e-atx template that shows the screw/mounting holes, see if they basically line up. My Nzxt Phantom 820 is an ultra-tower, larger than Area51, it accepts e-atx & xl-atx boards, but I'd have to take my mthrbrd out to see if the holes match my atx Asus board in there, sorry, I can't help with that answer, whether the holes match; from memory they do though (?). Keep searching online for a visual look at atx vs e-atx mounting holes relative to each other, you can even do a sight comparison of Asus atx boards and e-atx boards looking for mounting holes - to me, it looks like the Rampage's holes match atx, & the board simply "overlaps" an inch
e-atx board mount holes need to match up w/tempan; any that don't need to be insulated from the mb. Where this stock mthrbrd's edge dies at the outer right screw holes, Rampage appears to simply scoot over an inch. Cable organizer needs remounted, moved over to the right an inch.
sight compare w/the Maximus 7 Formula atx board; the 9 mounting holes look to be the same, rampage overlaps "1.1 inches" from the three right mounting holes. With no guarantees, I'd say it'll attach to your tray just fine - if not, then the Formula (any atx) certainly will. You're making me want a Rampage Z99 now too (= I'd try it, but that's because I have a MicroCenter close by, & could return it if it din't work out.
To re-use your liquid cooler, message Asetek, see if they have a new 2011 v3 retention kit, that adapts new mb to old stock Asetek cooler. Here's their official eBay seller page, message them through there:
word of advice: whether you get an atx/e-atx Asus, since it's an Intel i7, you should be able to boot up with your current hard drive & Windows install: you would do this to test that your already installed Command Center & its AlienFx features are willing to work w/new MB. That's the fastest way to check.
FYI: Rampage (most Asus boards) only has 2 usb 2.0 headers (our stock board has three headers); you'll at 1st lose one of your top front usb 2.0 ports. Utmost, be sure you plug in your master i/o board's usb cable into one of the two headers, lest your mio not communicate w/new mb, simply because you chose to plug in the top front usb in its place by 'mistake'. Find/trace usb cable that's plugged into your m i/o board & have it plugged into mthrbrd usb header ... (it is labeled MB_1 & USB_3 @ either end of its cable) ... then boot up (or try to) w/your current hard drive to check Command Center/AlienFx & m i/o compatibility w/Asus Z99 etc. If all looks/acts good, you could then try a new Windows install. Best advice is to unplug mio usb cable from new mb during new windows install, then plug it in after .netframework4 is installed.
Post in the coming days/weeks if you have troubles/issues with CC-AFx, mio & new Asus. CC version 2.08.09 from Dell.com will install on Asus, 2.08.11 will not: proprietary software that needs a serious work-around.
Good luck with Haswell-E. Keep this post alive for your new build log, take/upload some photos as you progress, & write up a diddy if/when successful ...
Well.. I think it is much better to buy a new case and with totally new components otherwise it will be very complicated. Maybe I sell my Area 51.
... Awwww man, now you make me feel like I'm Captain Marko Ramius in Red October ...
- " Capitan vaiyul !!! " --> (Cap'n scared 'im outta the water !!!) -
Area51 MB swaps need a plan, & "the average Ruskie, son, don't take a dump without a plan."
Don't pull a Crazy Ivan ... engage the caterpillar drive ... I would like to have seen Montana ...
Give me a ping, Vasili. One ping only, please.