[Review] Round 2: Koolance CPU-350 and CPU-345 Tested

[Vapor]

Preface
This is a quick version of my Koolance CPU-350 and CPU-345 Testing....it's part five of my Roundup #2 of waterblock testing. The XS version has the boring parts cut out with basically just the core charts and the words

If you have any questions, check out the full review (link above)...if they're not answered, ask away here

Test Results

First up, individual mounts:

Wow! Talk about a lack of differentation between orientations (three were tested: with the barbs horizontally, vertically, and at a 45 degree angle). Also interesting was that the new midplate ("New MP") performed identically to the old one. In my previous tests, I noted a .25-.5C difference between the two, but I did something different this time: I marked the outside of the block with Sharpie so that I would reassemble the block identically--last time I assembled by feel. The flowrate of the old midplate configuration was 1.24GPM, easily the most restrictive stock configuration I've tested so far. The flowrate with the new midplate went up to 1.40GPM while noticing no degradation in thermal performance. Still shocking just how little this block cares about orientation--something rare from a high performance block these days.

The CPU-345 is quietly sitting back behind the CPU-350, but the difference was surprisingly small, only a ~1.7C drop in performance. The CPU-345 is very low restriction (about the same as the Heatkiller 3.0 LC) and has the same solid mounting mechanism that the CPU-350 uses. This block is a sleeper.

• Very High Pumping Power: All three MCP355 pumps and the D5 are on at full speed--this has a very similar PQ curve to a pair of RD-30s at 20V.
• High Pumping Power: Two MCP355s with EK V2 tops are on at full speed. The other two pumps are off.
• Medium High Pumping Power: A single MCP355 with XSPC V3 top is on at full speed. The other three pumps are off.
• Medium Pumping Power: The stock D5 is on at full speed and setting 5. The other three pumps are off.
• Low Pumping Power: A single MCP355 with XSPC V3 top is on at minimum speed (~7.7V, ~2450RPM). The other three pumps are off.
• Very Low Pumping Power: The stock D5 is on at minimum speed--setting 1. The other three pumps are off.

Note: I do 5 mounts at "Medium High" then take the best config of a block and test the whole flow spectrum (after a TIM curing session) then realign that curve with average of the 3 median mounts to give you the "Adjusted" data.

Many More Graphs
I've included the core graphs and data here...but there's more in the full review, which is here.

Conclusion
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.

[WaterFlex]

Thank you, Vapor

[MpG]

Geez, didn't see this earlier. I've been wondering for a while how the CPU-345 stacked up against what on the market lately, and it looks pretty nice. Thanks for the testing!

Any chance of internal shots? Koolance's site doesn't provide any, although they say the block can be opened. You say it has "pyramid pins", but it also seems to be performing better than my own past experiences with the 330 and 340 models.

[eponymous]

Thanks for this

[Vapor]

Geez, didn't see this earlier. I've been wondering for a while how the CPU-345 stacked up against what on the market lately, and it looks pretty nice. Thanks for the testing!

Any chance of internal shots? Koolance's site doesn't provide any, although they say the block can be opened. You say it has "pyramid pins", but it also seems to be performing better than my own past experiences with the 330 and 340 models.

Don't have my light tent and tripod here yet (grrrr), but here's a quick shot:

[Hondacity]

vapor

do you agree with these notes i have..with regards to improving the k350?

1. removing the 4 uncut corners(with arrows) and
2. bigger opening
3. bigger exit holes
3. removing the parallel fins..and just spreading the cris-cross cuts all over.
4. bigger diameter base(block) say 5mm

[Vapor]

1. I don't think that would do much
2. Possibly....there's probably some potential with changing the midplate. Bei Fei was going to make some for me, but I think he's been busy and I didn't want to bug him about it
3a. Yeah, if they could remove exit restriction, I think that would help a lot (no sense adding restriction if it's not functional restriction).
3b. I think that's there for manufacturing reasons--pins that small are really hard to make. An entire array of micropins (especially with a raised wall around the outside) would be tough to manufacturer, I believe.
4. So 345 size? Yeah, maybe. That was their standard size for awhile, there's probably a manufacturing reason why the 350 is smaller.

Extension of 3a--I'd actually like to try a midplate that has gaps at the end of the microchannels, rather than between the microchannels (though the way they have it equalizes pressure drop with a non-uniform top....it'd be a fun test anyway).

[MpG]

Don't have my light tent and tripod here yet (grrrr), but here's a quick shot:

Thanks. Yeah, the triangles are definitely finer than earlier models, definitely more pin surface area present. No surprise to see an improvement there.

[Bei Fei]

Bei Fei was going to make some for me, but I think he's been busy and I didn't want to bug him about it

My trade show machine shipped friday! I will have some extra time soon..... After I catch up my ECO work.