Thermal Testing
I’m using my new V2 radiator test bench for testing which nets significantly lower watts dissipated numbers than my old open air testing. This new bench is both insulated and shielded from getting any external cooling help and likely more accurately simulates a closed case condition. The tested parts are as follows:
Test Specifications:
- Thermal Sensor logging: Crystalfontz CFA-633, logs up to 32 temperature probes and up to 4 fan channels: http://www.crystalfontz.com/products/633/index.html
- Temperature Probes: Dallas Digital One Wire DS18B20 probes. These are good to about .2C absolute accuracy in normal water cooling temp ranges and have a nice fine .0625C resolution. Also since they communicate digitally, you can string the power, ground and Vdd wire in series between all the sensors limiting the amount of wires significantly.
- Pump: Swiftech MCP-35X2 at 40% PWM. Simulates medium pumping power and results in roughly 1.5GPM +- depending on radiator restriction.
- Block: Danger Den MC-TDX block
- Heater: Standard Aquarium 300W Heater with safety switch soldered in the closed position so heat remains on regardless of temperature. This requires removing the heater element from the glass tube, soldering the two tabs together and putting it all back together.
- Heater/Reservoir Bath: I fabricated this from 1″ schedule 40 PVC with a T and elbow to 1/2″NPT threaded fittings and then used NPT nylon barbs to connect tubing. The cap I had to use a 1-1/4″ threaded cap and turned it in my lathe to fit the exterior of the 1″ T fitting.
- Insulation was a combination of 1″ and 1/2″ pipe insulation cut to fit.
- Tubing is 3/8″ ID x 1/2″ OD tubing. Koolance 3/8″ barbs are also used as the test standard for thermal testing.
- Case Material – 1/2″ x 8″ Pine it’s a little over 24″ wide to barely fit 4x140mm rads. The bench overall height is about 18″.
- Inlet port was fabricated from a 4″ flange material making an ID opening of 4.540″ Diameter. I shaved the threads out of it and tapered the inlet on the lathe for a smoother inlet.
- Acrylic panels are all .100″ thickness and I dado cut slots into the shelves for them to fit into.
- Current Fan Controller is a Scythe Kaze Master, fed by a Koolance SPD-24 to slightly overvolt fans to 2200RPM.
- Heater Control is via a 3A generic Variac, although 5A would be better for higher heat loads. I am using the variac to dial in the Watts into the variac to 100W, 200W, and 300W for each RPM. 5Watts is then added for the pump heat minus variac heat, so each test is targeting approximately 105W, 205W, and 305W.
- For Watt Metering – P3 Kill-A-Watt and just manually observing and correcting wattage is used. Wattage normally does not vary by more than 2-3 Watts.
- Fans- Titan Kukri H PWM fans – I picked these fans because they had a good RPM range and I thought would better represent 25mm fan performance over using 38mm fans. They do have a more dense 9 blade fan design similar to the Gentle Typhoons. I’m not using them because I think they are superior in noise over other fans, I am simply using them because I can run them from about 650RPM clear up to 2200RPM to get a good broad range of RPM levels tested with a single fan type. They seem like a pretty good fan, but I wouldn’t suggest they are superior over other 25mm fans.
The GTX really prefers a bit stronger fans that what I provided in this test. You can see the trend line advancing to the top as RPMs increase, but performance really didn’t take off with these lower pressure 25mm fans until beyond about 1500RPM. You can see that it’s catching the MCR320-XP further towards the RPM limits tested and would likely surpass it beyond 2500RPM. I think GTX really is the ultimate radiator when it comes to unlimited fan performance. I’m thinking six Delta AFB1212VHE 38mm fans in push/pull levels of fan performance where noise is not a concern and the user simply wants the most heat dissipated possible regardless of noise. With that said, the GTX does still perform good even with weaker 25mm fans from about 1400RPM on upwards…it’s just not a radiator that is optimal running lower pressure 25mm fans at 1000RPMs or less…that Xtreme double dense core likes extreme fan power.
I should also note that while I am testing with a fixed pumping power, the GTX’s slimmer tubes should also make it have less loss in power with slower flow rates since the net velocity will be increased.
Summary Bar Chart
Much the same, the GTX really wants more fan power than the little 25mm Titan’s can provide, it would be in it’s prime with 3000RPM high pressure 38mm fans.
Nice review man, I really appreciate the time and effort you put into these reviews.
Cool massive necropost bro… [not]
Sorry, I ended up loosing a bunch of comments in my post mismanagement. There was some more active stuff in many of these posts and I had a mishmash of posting allowed or not. I finally figured out how to take them all and open up the comments again.
My fault..:)
@Martin
Eh?
The comments were all messed up and deleted on accident before which is why it look a bit empty is all.
Hi Martin,
The pressure drop curve is very unusually linear for this rad. I find yhst simply weird and illogical. Restriction dhould increase exponentially as flow increases, not in a linear manner. This brings me to beleive maybe something was off in your testing this one?!?!
I thought so too the first time I did a GTX, but it is correct, skinnee got the same flat curve. The only thing I can think of is the GTX uses unusually thin and flat tubes and as pressures increase these tubes must flex to the point of flattening the curve.
All of the GTX pressure drop tests have this same sort of flat response. Goes to show you not everything behaves theoretically though and there is probably some minor differences with some CPU blocks when mounted under bowing pressure vs free standing testing.