Asrock Extreme3 Gen3 = I5 2500K = Ram?

Mushkin Enhanced Blackline 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model 996776
http://www.newegg.com/Product/Product.aspx?Item=N82E16820226099

from the reviews people are running this ram with 1155 2500k fine
you should not be concerned with ram voltages as the processor is unlocked. you will be ocing it by upping the multi. you will not be ocing by raising the blk affecting the memory and the whole system.
 
@Elbert, @Alvine Wicked cool. Will take a look at those two :3

@mcnumpty Correct me if I'm wrong, but not every stick of ram will work in a motherboard.
 
Elberts link is ddr2133 so higher latency 11-11-11

recommended speed is 1600mhz latency 9-9-9 or lower no great advantage on sandybridge from ram speed

over 1600mhz

alvines link is still 1.65v

not all ram will be on the motherboard makers compatibility list--only the ones they decide to test--so as long

as you get the right ddr--ie ddr3 and right speed and voltage any should work really

if you are going to use a large heatsink then low profile ram may be a good idea

http://www.aria.co.uk/Products/Components/Memory/DDR3/Dual+Channel+1600MHz/Corsair+Vengeance+Low+Profile+8GB+%282x4GB%29+DDR3+PC3-12800C9+1600MHz+Dual+Channel+Kit+%28CML8GX3M2A1600C9%29+?productId=45511
 

This test with an i5 2500k shows performance advantages with every increase in RAM speed. Looks to me like the 1866 with 8 latency would be a good choice. With a 2~10fps difference in games I would suggest the faster RAM.
http://www.xbitlabs.com/articles/memory/display/sandy-bridge-ddr3_7.html

I would suggest the g.skills 8GB 1866 8 latency kit.
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231538&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-RSSDailyDeals-_-na-_-na&AID=10521304&PID=4176827&SID=1jsylqlqzlqmx