Thermaltake ToughPower GF3 850W ATX v3.0 PSU Review

The Thermaltake Toughpower GF3 850 is one of the first PSUs to fully support the ATX v3.0 spec and its challenging transient response tests, since it is equipped with a 12VHPWR connector. How it fares against similar capacity PSUs that don’t have the new PCIe connector? Read the review to find out! 

Thermaltake is making a hard effort in the last few years to enter the elite of the PSU brands. Several months after the official release of ATX v3.0, it announced the GF3 line, which includes PSUs with 12VHPWR connectors that meet the strict standards of Intel’s newest design spec. I have reviewed the lowest capacity GF3 unit, with 750W max power, so the next inline is the 850W model. All GF3 models but the highest capacity ones, 1350W and 1650W, are made by Channel Well Technology. The two models above are by High Power.

The GF3 850 uses a fully modular cable design and has Gold efficiency ratings by Cybenetics and 80 PLUS. It also has a Cybenetics A- noise rating, so its average noise output stays below 30 dBA, which is the average performance for this category. TT equipped the unit with a semi-passive fan mode for lower noise output, which can be deactivated should you need the fan spinning continuously. I am not a big fan of semi-passive mode since it applies higher stress to the PSU’s internals and FDB fans. It is better to have the fan spinning at low speeds under light loads, using PWM pulses to control it. This platform uses a dedicated fan speed controller, allowing for low speeds.


Cybenetics Report

Technical Specifications:

  • Manufacturer (OEM): CWT
  • Max Power: 850W
  • Cybenetics Efficiency: [115V] Gold (87-89%)
  • 80 Plus Efficiency: Gold
  • Noise: Cybenetics A- (25 – 30 dBA)
  • Compliance: ATX12V v3.0
  • Alternative Low Power Mode support: Yes
  • Power 12V: 850W
  • Power 5V + 3.3v: 120W
  • Power 5VSB: 15W
  • Cooling: 135mm Fluid Dynamic Bearing Fan (HA13525H12SF-Z)
  • Semi-Passive Operation: Yes (Selectable)
  • Modular Design: Yes (Fully)
  • High Power Connectors: 2x EPS (2x cables), 4x PCIe 6+2 pin (2x cables), 1x PCIe 12+4 pin (600W)
  • Peripheral Connectors: 12x SATA (3x cables), 4x 4-pin Molex (single cable)
  • ATX/EPS Cable Length: 600/700mm
  • Distance between SATA connectors: 150mm
  • Distance between 4-pin Molex connectors: 150mm
  • In-cable capacitors: No
  • Dimensions (W x H x D): 150 mm x 85 mm x 160 mm
  • Weight: 1.66 kg (3.66 lb)
  • Warranty: 10 years

Product Photos

The fan grille is too restrictive. With a more open one, the average noise output could be lower. Overall, the exterior design is interesting and doesn’t look dull, which is usually the case for PSUs.


All cables are long, and the distance between the peripheral connector is adequate. The 12+4 pin PCIe connector makes the difference with competing offerings. Soon enough, though, all PSUs with more than 750W capacity will have a 12VHPWR connector. Lastly, there are no in cable caps since the PCB is large enough to host all necessary filtering caps.

The 12VHPWR connector is rated for 300W, but in reality, it reports to the graphics card 600W since both of the sense pins are grounded. Given that the PSU’s capacity is not high enough to support 600W GPUs, TT should set the sense pins accordingly to allow up to 300W max power.

Protection Features

OCP (Cold @ 27°C) 12V: 88.6A (125.15%), 11.978V
5V: 30.5A (138.64%), 4.997V
3.3V: 30.9A (140.45%), 3.256V
5VSB: 4.7A (156.67%), 5V
OCP (Hot @ 43°C) 12V: 88.8A (125.44%), 12.025V
5V: 30.4A (138.18%), 4.999V
3.3V: 30.7A (139.55%), 3.251V
5VSB: 4.7A (156.67%), 4.995V
OPP (Cold @ 28°C) 1061.34W (124.92%)
OPP (Hot @ 43°C) 1067.91W (125.7%)
OTP ✓ (131°C @ 12V Heat Sink)
SCP 12V to Earth: ✓
5V to Earth: ✓
3.3V to Earth: ✓
5VSB to Earth: ✓
-12V to Earth: ✓
PWR_OK Accurate but lower than 16ms
SIP Surge: MOV
Inrush: NTC Thermistor & Bypass relay

OCP at 12V and OPP are correctly set. Typically, OCP is sky-high on the minor rails. I wonder why they keep pushing OCP so high, especially at 3.3V. The rest protection features are present and working ok. There is a minor glitch in power ok signal’s hold-up time, which is slightly lower than 16ms.

Part Analysis

General Data
Manufacturer (OEM) CWT
Platform CSZ
PCB Type Double-Sided
Primary Side
Transient Filter 4x Y caps, 2x X caps, 2x CM chokes, 1x MOV
Inrush Protection 1x NTC Thermistor SCK-075 (7 Ohm) & Relay
Bridge Rectifier(s)
2x Yangjie Electronic GBU1506 (600V, 15A @ 100°C)
2x STMicroelectronics STF33N60M2 (600V, 16A @ 100°C, Rds(on): 0.125Ohm)
APFC Boost Diode
1x On Semiconductor FFSP0865A (650V, 8A @ 155°C)
Bulk Cap(s)
1x Rubycon (420V, 680uF, 2,000h @ 105°C, MXE)
Main Switchers
2x On Semiconductor
APFC Controller
Champion CM6500UNX & CM03X
Resonant Controller Champion CU6901VAC
Primary side: APFC, Half-Bridge & LLC converter
Secondary side: Synchronous Rectification & DC-DC converters
Secondary Side
+12V MOSFETs 6x International Rectifier IRFH7004PbF (40V, 164A @ 100°C, Rds(on): 1.4mOhm)
5V & 3.3V DC-DC Converters: 2x UBIQ QN3107M6N (30V, 70A @ 100°C, Rds(on): 2.6mOhm) &
2x UBIQ QM3054M6 (30V, 61A @ 100°C, Rds(on): 4.8mOhm)
PWM Controller(s): uPI-Semi uP3861P
Filtering Capacitors Electrolytic: 3x Nichicon (2-5,000h @ 105°C, HD), 4x Nichicon (4-10,000h @ 105°C, HE), 1x Rubycon (2-10,000h @ 105°C, YXF), 1x Nippon Chemi-Con (4-10,000h @ 105°C, KY), 1x Nippon Chemi-Con (4-10,000h @ 105°C, KYA)
Polymer: 10x Elite, 6x APAQ, 8x CapXon, 4x NIC
Supervisor IC Weltrend WT7502R
Fan Controller Microchip PIC16F1503
Fan Model Hong Hua HA13525H12SF-Z (135mm, 12V, 0.5A, Fluid Dynamic Bearing Fan)
5VSB Circuit
1x PS1045L SBR (45V, 10A)
Standby PWM Controller On-Bright OB2365T

The OEM is Channel Well Technology, the preferred choice for many brands nowadays. The platform’s code name is CSZ, and I have met it many times so far. This is a reliable and good-performing platform equipped with good parts in this unit. The PCB is large and under-populated, allowing for optimal airflow. Nonetheless, there are no proper heatsinks on the secondary side, so the cooling fan has to spin at high speeds under harsh conditions to cool down the 12V board. The soldering quality is good, and the good caps and the fluid dynamic bearing fan won’t have a problem with the extended warranty TT provides for this product.

Load Regulation

Load regulation should be within 1% on all rails.

Ripple Suppression

Ripple suppression is great!

Transient Response

Transient response at 12V is not among the best I have seen, but it is not bad either.

Transient Response ATX 3.0 & 12VHPWR Connector Tests

The PSU passed all ATX 3.0 tests. The voltage drops at 3.3V were very close to the lower limit.

Hold Up Time

The hold-up time is among the lowest in this category. Still, it is higher than 17ms, meeting the ATX spec’s requirement. This is not the case for the power ok signal’s hold-up time, which is below 16ms.


The PSU supports Alternative Low Power Modes.

Inrush Current

Inrush current is low with 115V but pretty high with 230V input.

Efficiency Normal, Light & Super-Light Loads

Efficiency should be higher with normal loads. With light loads, the platform scores way better.

Average Efficiency 5VSB

The 5VSB rail has high enough efficiency.

Vampire Power

Vampire power is low.

Average Efficiency

The average efficiency is not high.

Average PF

The APFC converter performs well.

Average Noise

The average noise output could be lower if the fan’s speed weren’t so high at increased speeds.

Fan Noise & Speed Maps @ 28-32 °C

The fan’s passive operation doesn’t last long if you push hard the minor rails, which is what I do in these tests. Nonetheless, the fan’s noise is low with up to 460-470W loads. You will be treated with more than 30 dBA with above 720W loads, and the 40 dBA mark is passed with more than 825W.

Overall Performance

The overall performance is close to competing offerings by be quiet! and Cooler Master. The XPG Core Reactor is a bit further, and the EVGA 850 G7 and Corsair RM850x are notably higher in this chart. With a tighter load regulation at 12V and better transient response on the same rail, the GF3 850 would be closer to the high-end competition.


Thermaltake is among the first to offer fully ATX 3.0 and PCIe 5.0 ready PSUs through its GF3 line. The 750W and 850W units successfully passed the strict transient response tests that the ATX 3.0 spec requires for units with 12VHPWR connectors. Whether the future GPUs will require such crazy demands since the RTX 4000 graphics cards don’t need ATX 3.0 PSUs, according to NVIDIA’s statements, is something that nobody can know. One this is for sure, though, that you should invest in a power supply that will be as future-proof as it gets, and this is possible through an ATX 3.0 unit featuring a 12VHPWR connector.

The GF3 850 faces intense competition from XPG, Corsair, and EVGA but none of these offerings come with a 12VHPWR connector, and they are not ATX 3.0 and PCIe 5.0 ready, too. So if you need to buy a PSU with a 12VHPWR connector out of the box, also compatible with Intel’s newest spec, your choices are limited. The GF3 850 is a fine choice and won’t empty your wallet.


Buy Corsair RM850x  Buy EVGA 850 G7  Buy XPG CORE Reactor 850  Buy Seasonic GX-850



  • Full power at 47°C
  • ATX 3.0 and PCIe 5.0 ready
  • High enough overall performance
  • High build quality
  • Properly set OCP at 12V and OPP
  • Quiet operation under normal conditions
  • Great ripple suppression
  • Highly efficient at light loads
  • High-performance APFC converter
  • Low inrush current with 115V
  • Low  vampire power
  • ALPM support
  • FDB fan
  • Lots of connectors, including 12VHPWR
  • Fully modular
  • Adequate distance between the peripheral connectors
  • 10-year warranty


  • High OCP on the minor rails
  • Average efficiency should be higher
  • The transient response at 12V could be better
  • The 12VHPWR connector allows for up to 600W, which is too much for this PSU

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7 thoughts on “Thermaltake ToughPower GF3 850W ATX v3.0 PSU Review

  1. Hi,

    I’m using this Power Supply with my Zotac 4090 AMP Extreme AIRO, and even in 110% power mode (495w) with my 5900x in PBO, my Cyberpower UPS shows maximum 790w at the line, with no restarts so far. Is this because of ATX 3.0 allowing 200% loads, and the 12vhpwr cable allowing 600w even if it is labeled 300w? Also, is it safe to keep this, or better to upgrade to the 1200w model, even though your first test sample didn’t pass the ATX 2.0 200% load? Thanks in advance for your reply!

    1. Ideally, I would suggest a 1000W PSU, but from the moment you don’t have restarts or any other system issues, you don’t need to replace your PSU.
      Don’t trust what the UPS says, because it cannot catch power spikes.

  2. I receive 2 GF3 850 both DOA waiting for 3rd from TT they will test befor sending, I hope it works, been waiting a week already so far a total od 2 weeks waiting for a good PSU.

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