Well, the first testing attempt came to an end very quickly. When the CPU temperature exceeded 60oC, the system rebooted. The second testing attempt also ended with no success: we reduced the processor clock speed to 4.06GHz and in this mode it could run just fine at 1.288V Vcore. AKUATEK eXtreme FS-92 system proved absolutely stable only when the CPU was working at its nominal 2.8GHz and reached the temperature of 63oC. And don’t forget, the first test session was carried out in an open testbed.
The manufacturer claims that the performance of AKUATEK eXtreme FS-92 is comparable to that of other external and internal liquid-cooling systems. I decided to reinstall this cooler and to double-check the contact between the cooler sole and the processor die, but I faced a very unpleasant incident. Suddenly one screw head fell off, when I tried to unscrew it.
It was either a defective screw, or maybe I applied too much effort, when I was tightening it up, or maybe the threading on the bracket got broken, I cannot tell you exactly. However, I failed to remove the rest of the screw even with the pliers: it stuck. Anyway, even if I could remove it I would still have to cut new threading on the bracket and look for a bigger screw… So, I had to give up the idea to check the cooler performance on the LGA775 platform. By the way, the thermal past footprint on the processor and the cooler sole was thin and even: there was no need to worry about the contact between these surfaces.
The next series of tests was performed on ABIT Fatal1ty AN8 SLI mainboard, since two cores of the AMD Athlon 64 X2 3800+ processor (2.0GHz, Manchester E6 core) can also provide quite a thermal workload when the CPU is overclocked to 2.8GHz and runs at 1.45V Vcore. Unfortunately, we couldn’t install the AKUATEK cooler the right way, because of the memory modules. Theoretically, we could have moved them into the DIMM slots located farther away from the processor socket, but this configuration didn’t pass the stability test. As a result, I decided not to sacrifice the stability and reliability and directed the airflow up towards the PSU. Besides, the tests were performed in an open testbed, so it didn’t really matter which way the cooler fan is facing.
Unfortunately, AKUATEK eXtreme FS-92 didn’t quite pass the tests again, even when we overclocked the CPU to 2.7GHz and left the Vcore nominal. Just as in case of our LGA775 platform tests, the system would lose stability after 60oC on the CPU. As for the CPU working at its nominal frequency, the AKUATEK eXtreme FS-92 system coped with its cooling just fine letting the CPU temperature reach 49oC.
If we could probably blame the defective retention for the failure on the LGA775 platform, then this time, everything went smoothly and we didn’t have any installation issues. Although there was a slight gap between the retention brackets and the PCB, it was no longer an issue when the screws were tightened up.