Welcome to my pressure drop testing of the XSPC RS240
I would like to give special thanks to Paul from XSPC for yet
another great product to review, the products I have tested have all
surprised me in the amount of attention XSPC gives towards top
performance at great prices. They really put 100% into making
products that perform well!
With this review I will focus on the pressure drop and flow
characteristics for this radiator.
Hydraulics and Pressure Drop Testing
most scientific way to determine a blocks hydraulic resistance is to test
pressure drop. Pressure drop is a measurement of pressure loss across a radiator
that varies with flow rate. This is basically a measurement of energy loss, and
directly influences how much flow rate you will have.
Digital Manometer 477 Mark V - Accuracy .5% of Full Scale. Range 0-20.00 PSI range, Resolution .01 PSI
Instruments 7520 Series 0-5GPM, 250mm scale - Accuracy 2% of Full Scale.
Range 0-5GPM, Resolution .1 GPM (can be interpolated to .02GPM)
- Water Source - Household water pressure - 50PSI at >5GPM - Because flow
rate readings are instantaneous, household tap water and water pressure are a
good and powerful source for pressure drop testing.
And my results are as follows, the pressure drop results are very very good!
And if you're not familiar with
what this means, I'm providing a relative chart below comparing a few
other published and tested curves to the acquired results. Keep
in mind these comparison
curves were based on other testing facilities, so there could be some
error in different test beds but pressure drop is generally a fairly
repeatable test if good equipment is used. The XSPC RS240 is
right near the
bottom of the group, it is the best flowing of the single row tube
style radiators, very nice. Upon careful inspection of the interior
from what I can see, these radiators flare the tube ends more than
others and this reduces entrances losses which helps lower pressure
drop, very nice!
This will allow you to maximize your system flow rates for excellent
thermal efficiency in your water blocks. This is yet another great product from XSPC with
bottom line performance.
So another important consideration with most people is cost. For
a fair cost comparison, I chose the good folks at watercoolingshop.com
since they carry both the XSPC and Thermochill PA series radiators.
At watercoolingshop.com the prices were including VAT as of 4-10-2008
XSPC RS240 = UV Blue £25.99
(Black = £23.99
Thermochill A120.2 = £49.99
HWlabs BI GTS240 = £30.98
So in terms of cost using the black RS240, you can save 23% over a GTS
240 radiator and 52% less than a Thermochill PA120.2, that's a great
First are my tabular results which includes
additional data like the air in and air out, etc. This is fairly typical of a
slim 21mm thickness lower density radiator optimized for low speed fans.
And this is the estimating chart where you can select a heat load in watts and
get an estimated water temperature. For example assuming I was running a 200
watt quad core setup using Ultra Kaze fans at 2930RPM, I would get about a 4.4C
delta. So if my ambient temperature was 20C, my water temperature would be
To estimate a heat load you can use the following
Also worthy of noting, like any radiator, there is
a significant performance increase between the ultra slow and ultra high fans,
in this case you nearly triple the performance using the high speed fans.
These are the c/w values plotted over the fan range, more than anything
this just shows you the overall testing is following a fairly
controlled trendline which is good, and c/w gains diminish as the RPM
And everyone wants to know what heat dissipated is. This is what
I call the 10C "Average Performance" delta where, where it's still
good, but not an extreme setup where 5C deltas are desired. With
this you can see that you could cool a wide range of different
components depending on the fan performance and there is about a 2.6X
performance gain using the 3000RPM 38mm high pressure fans vs. the
undervolted 1000RPM 25mm fans.
And this is the high performance 5C delta chart where water
temperatures are very cool and would provide extreme cooling
performance. You can cool a very hot overclocked quad core or
something in the 200W range with fans running about 2400RPM or higher,
or an overclocked dual core around 115W with slow speed 1350 RPM fans.
Or you could run a dual core and GPU, etc it all depends on the
actual heat load and fan used, but there are options available with
There you have it, a very low
pressure drop, low cost, and well performing compact radiator that can
suit many needs. Due to the low pressure drop of this radiator, I
would certainly consider running two or three in the same loop if it's
needed to gain the cooling capacity needs you are after. Use the
above guides to estimate your heat loads and water temperature.
If running two of the same radiator, simply take your actual heat
load and cut it in half over the two radiators. My recommendation
is to strive for a 5C delta if possible, but up to a 10C delta is
generally considered acceptable.