Thortech Thunderbolt 850 W Power Supply Review
Load Tests
Contents
We conducted several tests with this power supply, as described in the article, “Hardware Secrets Power Supply Test Methodology.”
First we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching the behavior of the reviewed unit under each load. In the table below, we list the load patterns we used and the results for each load.
If you add all the powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (e.g., the +5 V output working at +5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. In the “Total” row, we are using the real amount of power being delivered, as measured by our load tester.
The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test, both inputs were connected to the power supply’s single +12 V rail.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 6 A (72 W) | 13 A (156 W) | 18.5 A (222 W) | 25 A (300 W) | 31 A (372 W) |
| +12VB | 6 A (72 W) | 13 A (156 W) | 18.5 A (222 W) | 25 A (300 W) | 31 A (372 W) |
| +5 V | 2 A (10 W) | 4 A (20 W) | 6 A (30 W) | 8 A (40 W) | 10 A (50 W) |
| +3.3 V | 2 A (6.6 W) | 4 A (13.2 W) | 6 A (19.8 W) | 8 A (26.4 W) | 10 A (33 W) |
| +5VSB | 1 A (5 W) | 1.5 A (7.5 W) | 2 A (10 W) | 2.5 A (12.5 W) | 3 A (15 W) |
| -12 V | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) |
| Total | 173.4 W | 348.1 W | 508.6 W | 678.4 W | 850.2 W |
| % Max Load | 20.4% | 41.0% | 59.8% | 79.8% | 100.0% |
| Room Temp. | 44.8° C | 44.8° C | 45.8° C | 47.9° C | 49.5° C |
| PSU Temp. | 39.8° C | 41.3° C | 42.6° C | 44.1° C | 47.9° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Failed at +3.3 V |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 195.1 W | 385.6 W | 568.6 W | 769.0 W | 985.0 W |
| Efficiency | 88.9% | 90.3% | 89.4% | 88.2% | 86.3% |
| AC Voltage | 113.6 V | 111.8 V | 110.3 V | 107.6 V | 104.4 V |
| Power Factor | 0.921 | 0.972 | 0.985 | 0.991 | 0.994 |
| Final Result | Pass | Pass | Pass | Pass | Fail |
The Thortech Thunderbolt 850 W can really deliver its labeled wattage at high temperatures.
Efficiency was between 88.2% and 90.3% when we pulled between 20% and 80% of the unit’s labeled power (i.e., between 170 W and 680 W). At full load (850 W), efficiency was at 86.3%, just a tiny bit below the 87% required by the 80 Plus Gold certification. However, the 80 Plus certification tests are conducted at a room temperature of only 23° C, and efficiency drops as temperature increases.
Voltages were closer to their nominal values (3% regulation) during all tests, except for the -12 V output during test one, and the +3.3 V output during tests three (at +3.19 V), four (at +3.14 V), and five (at +3.09 V). Unfortunately, the +3.3 V output dropped below the minimum required (+3.135 V) during test five. The ATX12V specification says positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.
Let’s discuss the ripple and noise levels on the next page.