Water Jacket
The water-jacket really is the core of any water-cooling system. It doesn't matter how good the rest of the rig is, if the jacket is not sucking the heat off the CPU then the exercise is pointless. Senfu's water-jacket looks like a basic socket370 unit, but as mentioned before it comes with mounting clips for SECC1 and SECC2 processors. This versatility is great as it future-proofs the system to some extent - you can be pretty confident of using it on your future CPU's as well as your current one. Included with the jacket are a few goodies - some thermal paste, some sticky foam for insulating things should they drop below room temperature, a spare o-ring and more tubing than you could possibly need. The metal plate and pins, packed with the jacket in protective foam, are for mounting the system on the various CPU's.

The instructions included with this unit are, quite frankly, woeful. They look like they're been photocopied a few times, making the diagrams almost unreadable (not that they were very clear to begin with). The text brushes over some important points and is quite confusing in parts. They provide full instructions for assembling the water-jacket and ensuring the o-ring is present, but the unit is shipped to you assembled. Given the presence of an o-ring in the little plastic bag of spare bits, I wasn't sure if the unit really was complete or not, so I pulled it apart to be sure. It is complete with o-ring intact - the o-ring in the bag is a spare. Still, it gave me a chance to check out how the unit is assembled and sealed. It really does clamp down very tightly on the o-ring, with no less than 8 screws, so I think it would withstand a fair bit of pressure. Senfu even provide a little screwdriver in the kit but it's useless, too small to get enough leverage for tightening the screws and too easy to strip the screwheads. I think they could forget the whole free screwdriver thing, given their target audience is people who are intending to water-cool their PC's they could safely presume the customer owns some decent screwdrivers.. and let's not forget that the unit is shipped assembled anyway!

The water path is nice and convoluted, which is good - Senfu have also made the channel bottom irregular to increase surface area and promote turbulence which is important inside the jacket - planar flow, where the water smoothly rushes past the metal surfaces, is bad. You want high pressure against the sides and bottom of the channel and making sure the water is turbulent is a simple way to do this. I imagine the jacket would trap air-bubbles in those little indentations, though - giving it a firm tap while the system is running should help them get blown out of the system. Air is a great insulator and hence not what you want in your water jacket.

The unit itself looks cheaply made - roughly cast from aluminium and, while this helps the cause of keeping the price down, a bad side-effect is that the bottom of the jacket is not very smooth. A smooth, high-pressure join is needed between the CPU and water-jacket and Senfu's unit was slightly scored and scratched with machining marks on the bottom - this could lead to air gaps and hence bad thermal transfer. You might want to consider sanding this unit flat before use - the technique I describe here for sanding mendocino Celeron slugs would work well with this unit. The hoses attach by sliding over an inner lug and a screw-on outer sleeve holds them in place. This arrangement works well but can be a little fiddly to fully tighten - the sleeves are quite thin so using pliers is probably not a good idea, you might inadvertently crush them. Grit your teeth and do it by hand.

I'll harp on about the poor documentation a little more - Senfu really need to address it. For example, they include one diagram for "Slot" CPU's. This ignores the fact that SECC CPU's (P2, Athlon) and SECC2 CPU's (P3) are fundamentally different in how you mount heatsinks to them. Futhermore, OEM and retail cpu's also differ in that some have a plate for attaching an aftermarket heatsink+fan and some have a full heatsink+fan assembly built on. Senfu have included screw-mount bolts of 2 sizes but I couldn't work out where the large ones are supposed to be used - it must be a type of CPU I don't have here (either a retail Athlon, retail P2 or OEM P3). Having said all that, I'm sure you could mount this unit, with varying effectiveness, on pretty much any PC CPU, retail or OEM. You might have to sit and experiment a bit with the mounting parts but I think Senfu have covered all the options.

One of the good things about this jacket is that the pipes enter and exit via the side, and it can be mounted in any orientation. This means that it would probably not block any ram slots on any Slot-based motherboard. If you tried to use it on a socketed (PPGA or FC-PGA, for example) motherboard then you might be restricted in how you orient the unit to avoid the tubing fouling any capacitors etc near the socket.