This conclusion is, as usual, pretty cut and dry. The CPU-350 is a great performer, coming within a quarter of a degree of the vaunted HK3.0LT in my tests. Yeah, it’s more restrictive, but the updated midplate alleviates some of the restriction. The mounting system is significantly better than the XSPC/EK/HK/DangerDen variety, but still a step behind the Swiftech/D-Tek offerings. One big improvement to the mounting system would be if the included threaded rods would stop at the right pressure (much like Swiftech’s setup). The CPU-350, like other radial flow blocks (Fuzion V2, Sapphire Rev.A, Apogee XT), has a pretty good resilience to reduced flow as well. One big plus about this block is that any orientation will get you the best results–if for any reason you need to rotate it, you’ll see no performance hit.
The CPU-345 is a really intriguing block. It’s extremely low restriction, well priced, well made, and has surprisingly good performance. It beats the Apogee GTZ, the Supremes, and the Enzotechs. Surely more blocks will fall behind it as my testing continues. It has the same (and really good) mounting system from the CPU-350 now, and is a pretty understated in terms of looks. I only did a few test mounts to test its orientation preferences, but it seems to share that quality from its older sibling–it just doesn’t care which way it’s oriented.
Both of these blocks are great. The CPU-350 has flagship performance, being imperceptibly close to the HK3.0LT in thermals while the CPU-345 is a really competitive (and unknown) mid-tier block.