Q6: VRM heatsinks can be topped with an 80 mm fan. Does it make sense to do so? In other words, how greatly will the use of a fan lower the VRM temperatures?
A: To answer this question we tested our graphics card with Thermalright Spitfire on the graphics processor (with Noctua NF-P14 fan at 900 RPM) and the VRM-R5 heatsink over the voltage regulator components in passive and active mode (with an 80 mm GlacialTech GT-8025 fan at 1600 RPM):
By adding another 80 mm fan to Thermalright VRM-R5 we could lower the voltage regulator components temperature of the Radeon HD 5850 graphics d overclocked to 910/4800 MHz by another 19-20 °C compared with the passive mode.
Q7: How does Thermalright Spitfire efficiency compare against that of alternative graphics card coolers?
A: To answer this question let’s compare the performance of our today’s hero against two very efficient solutions: Thermalright T-Rad2 GTX and Arctic Cooling Accelero Twin Turbo Pro paired with a VRM-R4 heatsink in passive mode:
Accelero Twin Turbo Pro worked with default cooling fans at 1100 RPM and at their maximum speed of 1960 RPM. Thermalright T-Rad2 GTX was tested with 92 mm Thermalright TR-SL-92-1500 fans working at 1000 RM and their maximum speed of 1540 RPM, which is still an acoustically comfortable mode for the fans of this size. Besides these coolers, we also included the results for the reference Radeon HD 5850 cooling system in auto mode and at maximum fan rotation speed. Before we proceed to the results, I would like to add that Thermalright VRM-R4 heatsink as well as VRM-R5 were installed over a layer of thermal paste instead of the default thermal pads. The testing conditions were exactly the same as before: case with a removed side panel and ambient temperature at 25.8-26.1 °C.
The results are summed up on the diagram below:
Thermalright Spitfire is an undefeated leader in terms of Cypress GPU air-cooling. It demonstrates astonishing advantage over the competitors. It would be enough to say that Spitfire cooler equipped with a 140 mm fan at 900 RPM cools the graphics processor under FurMark workload the same way Thermalright T-Rad2 GTX and Arctic Cooling Accelero twin Turbo Pro do with both their fans at maximum rotation speed. And most importantly the same is true for the load created by 3DMark2006, too! Excellent cooling efficiency, great job, Thermalright! At the same time I have to say that the voltage regulator components on the overclocked Radeon HD 5850 cooled by Thermalright Spitfire and VRM-R5 heatsink run hotter than in case of two alternative coolers bundled with VRM-R4. The explanation would be pretty simple in this case: both – T-Rad2 GTX as well as Accelero Twin Turbo Pro direct the airflow towards the graphics card, while the Spitfire fan blows the air parallel to the card. On the other hand, even the peak temperature of 63 °C on the voltage regulator components during FurMark test is not something you should really worry about.
Q8: Can Thermalright Spitfire be installed with the heatpipe ends facing down so that it doesn’t interfere with tower coolers over the CPU, and how will this positioning affect its cooling efficiency?
A: Unfortunately, when Thermalright Spitfire was turned with its heatpipes facing down, we couldn’t install the graphics card into any of the available PCI-E slots on the board, because Spitfire cooler was hitting against the power supply unit (or it would hit against the bottom of the system case). Moreover, in this case you won’t be able to fasten the heatsink using the additional default retention kit.
Q9: Can Spitfire be installed onto Radeon HD 5870/5850 with the reference heatsink plate left over the memory chips and the voltage regulator components?
A: No, it cannot. Spitfire heatpipes go straight up and this plate won’t let you put the cooler onto the GPU. Of course, you could cut out a piece from this plate, but in this case you will definitely lose the graphics card warranty.
Q10: How much cooling efficiency will be lost if we use aluminum heatsinks enclosed with Thermalright Spitfire for the voltage regulator components of Radeon HD 5870 and HD 5850 graphics cards as opposed to VRM heatsinks?
A: Of course, you can use the enclosed heatsinks for the voltage regulator circuitry, but in this case the VRM temperature will be 30°C+ higher depending on the overclocking and type of operational load.