Performance
Our benchmarks begin with the 105W AMD Ryzen 9 5950X CPU operating at stock speeds. We run the popular Cinebench R23 multi-core benchmark for an extended period and chart the average CPU temperature from the last five minutes of 100 per cent load.
The two 420mm all-in-ones take the top two slots, with the Arctic establishing an early lead over the Corsair, but what is clear is that this level of cooling is overkill for a stock-clocked chip; even a single-fan air cooler will suffice.
At stock settings noise levels are suitably quiet at all times.
Upping the ante while maintaining complete stability, we raise the CPU multiplier to 45x on all cores and increase voltage to 1.25V. The modest overclock pushes CPU power up to 200W and represents a sterner challenge for coolers of this ilk.
This is where superior cooling begins to prove its worth, and once again the 420s retain the same formation. Arctic holds the lead, but the H170i reduces delta temperature by almost 10 per cent over the 280mm H115i.
There is a caveat to that cooling advantage in that three fans may prove noisier than two. In our setup, the H170i is slightly more vocal than the H115i when the going gets tough. There's not a lot in it, mind, and the bigger problem for Corsair's flagship is that the much more affordable Arctic Liquid Freezer II continues to hog the top spot.