are they h100i fans any good or will i have to buy sp120

Well the above answer is not quite correct. When people switch out the 2700 rpm fans on the H100i, they generally switch them out for SP120s of a different rpm to reduce noise.

2350 rpm SP120s
http://www.newegg.com/Product/Product.aspx?Item=N82E16835181040

1450 rpm Corsair SP120s
http://www.newegg.com/Product/Product.aspx?Item=N82E16835181042

The fan dilemma on the H100i is a conundrum.....

The H100i manages to eke out a slight win against the better air coolers by by using 2700 rpm fans .... it's not that the cooler itself is any any way more efficient, it's just that when it comes to cooling, 2700 rpm beats 1200 rpm.

The downside of course to 2700 rpm fans is noise.

http://martinsliquidlab.org/2013/03/12/swiftech-h220-vs-corsair-h100i-noise-testing/

Once the CPU load hits 55% (about 1:15 mark in above video) the noise gets annoying ..... at the 60% loading (1:45), I wanna leave the room. At 90% it's louder than my vacuum cleaner.

So of course switching out the fans to lower rpm will make it quieter. The problem is, slowing down the fan fpm means cutting the thermal performance of the unit to a point where ($100 for H100i + $30 for fans) you could buy the Swiftech 220-X which:

1. Beats any CLC (Closed Loop Cooler) hands down
2. Does it 20 dbA quieter .... in other words, it's 1/4th as loud as the H100i
3. It's an OLC (Open Loop Cooler) meaning at any point in the future, you ca "open" the loop and add more blocks.


They pretty much sell out as soon as new stock arrives so Swiftech been selling them at full MSRP ($139.95)....expect they will be $120 - $130 when they arrive at newegg

http://www.frozencpu.com/products/25187/ex-wat-327/Swiftech_H220-X_Expandable_All-In-One_Liquid_Cooling_Kit.html?tl=g30c321s818
http://www.swiftech.com/H220-X.aspx

Reviews:

9.9 rating for 220-x http://www.techpowerup.com/reviews/Swiftech/H220-X/9.html
http://www.hitechlegion.com/reviews/cooling/liquid/40870-swiftech-h220-x-open-loop-240mm-cpu-cooler-review?showall=&start=3
http://www.overclockers.com/swiftech-h220x-cpu-liquid-cooling-kit-review