There's such a scarcity of information about them online (that's probably part of the reason why they're so cheap)...
I have over 16 systems using E5-24xx cpus. If you search for my posts, you see more info.
I mentioned earlier this year, $100 system board, with 2 x E5-24xx cpu == $250 total , still cheaper than an I7-4xxx cpu.
Intel H2312JFJR Server with dual E5-2430L 6c/12t @ 2.00 ghz , 48gb mem
CineBench 1140cb
SuperMicro X9DBL-iF single E5-2430L with 24gb Windows 2012 R2 CineBench R15 = 561 cb
power consume 40-50w idle
WS12R2 with E5-1428L 6c/12t , idle at 32w , Prime95 load 88w
CineBench R15 451cb
Tyan Intel Server Motherboard S7045GM4NR Dual LGA 1356
Dual E5-2430L , 6 x 4gb mem , 1 hard disk , WS2102r2 idle at 56w
CineBench R15 : 1146 CB