The card
ASUS decided to equip the Radeon R9 390X STRIX Gaming 8GB with a new version
of their famous DirectCU cooler. This is actually the third version of it and they decided to come up with a triple fan cooler. In the case of this card you get no less than
five heatpipes, one measures six millimeter, two measure eight millimeter and two offer massive ten millimeter diameter. As with the DirectCU II cooler there is no base plate. ASUS actually communicates, that this should help decreasing temperatures even further, since there are less heat transfers. If you have a very close look at the heatpipes, you notice that there are rather large gaps inbetween the pipes. These gaps need to be filled with enough thermal compound. Apart from that this has has uneven cooling as a result, since the layer of thermal compound in the gaps is much thicker than between the GPU and the heatpipe. This actually leads to the point that cooling is not provided to the GPU uniformly, when there is the so called "Direct Touch" approach in place. Apparently this is nothing to worry about, but in countless cooler reviews we noticed, that models with a copper baseplate perform better than others with Direct Touch Heatpipes.
Soldered to the heatpipes you find the fin stack which is being
provided with fresh air by three fans, which are being manufactured by Everflow. The fans on the new STRIX Gaming series cards are designed to spin only when the GPU temeprature reaches 65 degrees, which means that in 2D mode they are completeley off. Also, under low loads the fans don't start to spin. Under high-load the noise level is still silent, subjectively
speaking.
The ASUS Radeon R9 390X Gaming 8G graphics card, or to be precise our sample of
it, allowed a maximum stable overclock of 1'250 MHz
for the GPU and 1'725 MHz on the memory side. With these clocks we had to feed the GPU
with 1.352 Volts and the memory ran at stock voltages.
A closer look at the PCB shows that ASUS equipped this graphics card with
a 8+2+1
phase power design. The GPU gets its current from eight phases, two memory can rely on two phases and PLL is handled by another phase..
Checking the voltage regulation chip we find an ASP1300, which is taking care of GPU phases. Apart from that there is UP1641p in charge of PLL power distribution. In general the configuration of MOSFETs is rather interesting on this card, consisting of four M3055M, two M3054 and six MPSF03 DrMOS chips.
The memory chips on the Radeon R9 390X STRIX Gaming 8GB come from SK Hynix and carry the
model number H5GC4H24AJR. They are specified to run at 1'500 MHz (6'000 MHz
effective).