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This is the 26th radiator I have reviewed, and yet only the first cross-flow type radiator. Over an year ago, we took a look at the Alphacool ST30 480 here, and I did not even have to say it was a more standard “U-Flow” radiator because it was simply assumed as such. Dual pass radiators have become the norm now for a good reason- it offers an optimum balance of performance and liquid flow restriction. Some radiator manufacturers have gone beyond dual pass radiators for some models: Mayhems with their quad pass Havoc radiator, or even the recently seen Watercool MO-RA3 with all of 20 passes. The higher the number of passes, the better (generally) the contact area with fins and theoretically better the heat transfer rate. On the other hand, single pass cross-flow radiators are among the rare that have an odd number of pass meaning that the inlet and outlet port(s) are on opposite sides of the radiator. This allows for a more cyclical loop and a different tubing layout. A single pass also means lower liquid flow restriction relative to a dual pass radiator, all other things being equal. There is a hit in performance, however, so this is why there are not many of these in the market today. Alphacool wants to do something about it, and has released a whole range of such radiators. Today we take a look at their ST30 model, so let’s thank Alphacool for the review sample and get right to it.

Here’s a look at the specs from the product page:

Case: Steel
Color: black
Connector: 4x G1/4
Cooling channels: Copper
Dimensions (L x B x H): 532 x 124 x 30 mm
Fan mounting thread: M3
Fan size: 120 mm
Fins per inch: 16
Manufacturer: Alphacool
Material lamellae: Copper
Number of fans: 4
Pressure tested: 1,5 Bar
Thickness: S – 30 mm

Technical specifications:
Material internal: Mostly copper 
Material casing: Side panels steel, threads brass, copper chambers
Colour: Black
Dimensions (LxWxH): 532 x 124 x 30 mm 
Radiator size: 4×120 mm
Connection threads: 4×1/4“
Mounting thread size: M3
Pressure tested: 1.5 bar
Weight: 853 g

Extent of delivery:
1x Radiator
2x screw plug
Mounting material

Alphacool also provides a technical drawing which is very handy in measuring out space for the radiator inside a case and accounting for tubing as well even before your purchase it. Note that cross-flow radiators are generally longer than dual pass U-flow radiators, so please do check the dimensions and make sure it will fit. That aside, there is not much else different here from the ST30 480 we already took a look at, with a mostly copper internal (not full copper, it is still a brass alloy in the tubes and the ports) and the ST model remaining at 30 mm thick overall. Interestingly, the X-Flow naming has been adopted by many before, such as HWLabs with their original GTS rads, but it seems to have become synonymous with cross-flow radiators as U-flow has with dual pass radiators. Alphacool has a 2 year warranty here, which is okay for a radiator as any real issues will pop up almost immediately anyway. Let’s now take a detailed look at the radiator on the next page.

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