Buying Guide
The Best Quiet Power Supplies
We weighed five power supplies on rated output and native 12V-2x6 cable count; the Thermaltake Toughpower GT 850W has the highest rated output, and the Thermaltake Smart BM3 650W costs the least.
By Alex Morgan, PC Hardware Editor
12 min read5 products evaluated
A power supply is quietest when its fan can stop at idle and light gaming loads. Every pick has a fan-stop mode, ordered from the lowest price.
Rankings weigh wattage, native 12V-2x6 cables and warranty as the makers state them; we did not test these power supplies ourselves, and if a maker skips native 12V-2x6 cables, the guide says so.
Quick Picks
Which of the 5 picks to look at first. Tap a name for the full analysis.
Lowest Price Here
Thermaltake Smart BM3 650WA lower price than the SAMA GT650 White and the rest when we checked.
Best for: Spending as little as possible, with the SAMA GT650 White the next step up.
Check price for Thermaltake Smart BM3 650W on Amazon (opens in a new tab)
Also Consider
SAMA GT650 WhiteAn ECO silent mode for low-load quiet.
Best for: Buyers who want ECO silent mode for low-load quiet.
Check price for SAMA GT650 White on Amazon (opens in a new tab)
Strong Alternative
SAMA GT750Japanese capacitors with an LLC and DC-DC design.
Best for: Buyers who want Japanese capacitors with an LLC and DC-DC design.
Check price for SAMA GT750 on Amazon (opens in a new tab)
Longest Warranty
MONTECH Century II 550WThe longest warranty here (10 years).
Best for: Buyers who put warranty first.
Check price for MONTECH Century II 550W on Amazon (opens in a new tab)
Highest Rated Output
Thermaltake Toughpower GT 850WThe highest rated output here (850W).
Best for: Buyers who put rated output first.
Check price for Thermaltake Toughpower GT 850W on Amazon (opens in a new tab)
Our Picks
Lowest Price Here1 of 5
Thermaltake Smart BM3 650W
The Thermaltake Smart BM3 650W stands out for Japanese 105°C main capacitor, and it adds semi-modular cables: fixed main cables, detachable extras.
Best for
- Spending as little as possible, with the SAMA GT650 White the next step up.
Skip if
- Choose another pick if you can't accept this: a shorter 5-year warranty.
Why we like it
It also offers a 650W rated output and offers a 5 years warranty. It is 80 Plus Bronze and ATX 3.1 compliant for PCIe Gen 5 cards, with industrial-grade protections built in. It matches the SAMA GT650 White on rated output (650W).
On warranty it ties with the Thermaltake Toughpower GT 850W at 5 years. It is the only pick here with a bronze 80 plus rating; the MONTECH Century II 550W has a gold 80 plus rating instead. Semi-modular cabling is unique to it among these picks, while the SAMA GT750 uses fully modular cabling.
The Thermaltake Smart BM3 650W has no stated native 12V-2x6 cable; confirm the cable kit before pairing it with a 16-pin card. No depth is rated for the Thermaltake Smart BM3 650W, so check the maker's page against your case's PSU bay. No other pick here cost less at our last price check, and the SAMA GT650 White was closest.
Key specs
- Wattage
- 650W
- Warranty
- 5 years
- 80 Plus rating
- Bronze
- ATX version
- ATX 3.1
- Form factor
- ATX
- Cabling
- Semi-modular
- Fan
- 120mm
- Fan stop
- Yes
- Colour
- Black
Pros
- A 650W rating
- ATX 3.1 compliance
- A fan that stops at low load
- Japanese 105°C main capacitor
Cons
- A shorter 5-year warranty
- Only 80 Plus Bronze efficiency
- No published native 12V-2x6 cable count
The catch
If you want a confirmed native 12V-2x6 cable count, look to the SAMA GT650 White instead: it offers 1, while this one gives no figure.
Also Consider2 of 5
SAMA GT650 White
SAMA's GT650 White is a fully modular white unit with embossed white cables, a native 12V-2x6 cable and an ECO silent mode.
Best for
- Buyers who want ECO silent mode for low-load quiet.
Skip if
- Its warranty is not published, which rules it out if you need that number.
Why we like it
Japanese capacitors support long-term durability, and a native 12V-2x6 connector feeds current graphics cards. It is 80 Plus Gold rated. On rated output it ties with the Thermaltake Smart BM3 650W at 650W.
You get a white colour here, which sets it apart from the Thermaltake Toughpower GT 850W and its a black colour. The SAMA GT650 White comes with a native 12V-2x6 cable, so a 16-pin card plugs in without an adapter. No depth is rated for the SAMA GT650 White, so check the maker's page against your case's PSU bay. On price it sat second of 5, between the cheaper Thermaltake Smart BM3 650W and the pricier SAMA GT750, at the time of writing.
Key specs
- Wattage
- 650W
- Native 12V-2x6 cables
- 1
- ATX version
- ATX 3.1
- Form factor
- ATX
- Cabling
- Fully modular
- Fan
- 120mm
- Fan stop
- Yes
- Colour
- White
Pros
- A 650W rating
- A native 12V-2x6 cable for 16-pin cards
- ATX 3.1 compliance
- Fully modular cables
Cons
- No published warranty
- Costs more than the Thermaltake Smart BM3 650W at the time of writing
The catch
The maker doesn't give its warranty; if that figure matters, the MONTECH Century II 550W offers 10 years.
Strong Alternative3 of 5
SAMA GT750
SAMA's GT750 uses Japanese capacitors with an LLC and DC-DC design, a native 12V-2x6 cable and an ECO silent mode for low loads.
Best for
- Buyers who want Japanese capacitors with an LLC and DC-DC design.
Skip if
- Skip it if you need to know its warranty before buying; the maker doesn't publish one.
Why we like it
Its ECO silent mode keeps the 120mm FDB fan quiet at low load, and Japanese capacitors with LLC and DC-DC topology support long-term stability. Embossed modular cables are easier to route. Its embossed modular cables improve airflow and make routing simpler.
Its 750W rated output ranks second of 5 here, behind the Thermaltake Toughpower GT 850W (850W) and ahead of the MONTECH Century II 550W (550W). The SAMA GT750 comes with a native 12V-2x6 cable, so a 16-pin card plugs in without an adapter. No depth is rated for the SAMA GT750, so check the maker's page against your case's PSU bay. When we checked, only the SAMA GT650 White and cheaper picks cost less, and the MONTECH Century II 550W cost more.
Key specs
- Wattage
- 750W
- Native 12V-2x6 cables
- 1
- Cybenetics rating
- Gold
- ATX version
- ATX 3.1
- Form factor
- ATX
- Cabling
- Fully modular
- Fan
- 120mm
- Fan stop
- Yes
- Colour
- Black
Pros
- A 750W rating
- A native 12V-2x6 cable for 16-pin cards
- ATX 3.1 compliance
- Fully modular cables
Cons
- No published warranty
- Costs more than the Thermaltake Smart BM3 650W at the time of writing
The catch
If you want a confirmed warranty, look to the MONTECH Century II 550W instead: it offers 10 years, while this one gives no figure.
Longest Warranty4 of 5
MONTECH Century II 550W
Montech's Century II 550W is a fully modular 80 Plus Gold unit with a native 12V-2x6 cable and a 10-year warranty, unusual at this wattage.
Best for
- Buyers who put warranty first.
Skip if
- Skip it if rated output matters most to you; the Thermaltake Toughpower GT 850W offers 850W.
Why we like it
Its 135mm FDB fan has a zero RPM mode, and it uses 100% Japanese capacitors. The silver metallic finish is MONTECH's signature look. It is ATX 3.1 and PCIe 5.1 ready with a 12V-2x6 cable.
On rated output it trails the group at 550W, while the Thermaltake Toughpower GT 850W offers 850W. Its 10 years warranty is the longest here; the Thermaltake Smart BM3 650W comes next at 5 years. It shares a gold 80 plus rating with the Thermaltake Toughpower GT 850W; the Thermaltake Smart BM3 650W goes with a bronze 80 plus rating.
It also offers a 135mm fan that can stop at low load. The MONTECH Century II 550W comes with a native 12V-2x6 cable, so a 16-pin card plugs in without an adapter. Its price falls between the SAMA GT750 and the Thermaltake Toughpower GT 850W, based on our last check.
Key specs
- Wattage
- 550W
- Native 12V-2x6 cables
- 1
- Warranty
- 10 years
- 80 Plus rating
- Gold
- ATX version
- ATX 3.1
- Form factor
- ATX
- Cabling
- Fully modular
- Fan
- 135mm
- Fan stop
- Yes
- Colour
- Black
Pros
- A 550W rating
- A native 12V-2x6 cable for 16-pin cards
- A 10-year warranty
- ATX 3.1 compliance
Cons
- Rated output trails the Thermaltake Toughpower GT 850W (850W)
- Costs more than the Thermaltake Smart BM3 650W at the time of writing
The catch
If rated output is your priority, the Thermaltake Toughpower GT 850W (850W) is the stronger choice.
Highest Rated Output5 of 5
Thermaltake Toughpower GT 850W
Thermaltake's Toughpower GT 850W is a fully modular ATX 3.1 unit with a native 12V-2x6 cable, a single high-amperage 12V rail and a Smart Zero Fan mode.
Best for
- Buyers who put rated output first.
Skip if
- Pass on it if a shorter 5-year warranty rules it out for your setup.
Why we like it
Smart Zero Fan keeps the fan off at low load, and its low-profile flat black cables are easy to route. It is 80 Plus Gold rated at up to 90% efficiency. On rated output it leads this guide at 850W, ahead of the SAMA GT750 (750W).
On warranty it ties with the Thermaltake Smart BM3 650W at 5 years. Like the MONTECH Century II 550W, it has a gold 80 plus rating, while the Thermaltake Smart BM3 650W uses a bronze 80 plus rating. The Thermaltake Toughpower GT 850W comes with a native 12V-2x6 cable, so a 16-pin card plugs in without an adapter.
No depth is rated for the Thermaltake Toughpower GT 850W, so check the maker's page against your case's PSU bay. At our last price check it topped the group, with the MONTECH Century II 550W the nearest cheaper option.
Key specs
- Wattage
- 850W
- Native 12V-2x6 cables
- 1
- Warranty
- 5 years
- 80 Plus rating
- Gold
- ATX version
- ATX 3.1
- Form factor
- ATX
- Cabling
- Fully modular
- Fan stop
- Yes
- Colour
- Black
Pros
- A 850W rating
- A native 12V-2x6 cable for 16-pin cards
- ATX 3.1 compliance
- Fully modular cables
Cons
- A shorter 5-year warranty
- Warranty trails the MONTECH Century II 550W (10 years)
- Costs more than the Thermaltake Smart BM3 650W at the time of writing
The catch
Native 12V-2x6 cable count is its weakest area, and the SAMA GT650 White covers it better at 1.
How We Chose These Quiet Power Supplies
Alex Morgan compared the manufacturer specifications, connectivity, warranty terms and compatibility of every pick. Figures come from the makers unless a third-party source is named; we did not test these products ourselves.
- The figures behind the order
- We lined up five power supplies on rated output, native 12V-2x6 cable count, warranty and 80 Plus rating, using each maker's published specs. We did not test them in-house, and native 12V-2x6 cable count and warranty are missing for at least one pick.
- What every pick has in common
- All 5, from the Thermaltake Smart BM3 650W to the Thermaltake Toughpower GT 850W, state rated output, ATX version and form factor and share ATX 3.1 ATX version and fan stop.
- Where the specs have gaps
- The Thermaltake Smart BM3 650W gives no native 12V-2x6 cable count; the SAMA GT650 White and the SAMA GT750 give no warranty.
- Price range
- From the Thermaltake Smart BM3 650W to the Thermaltake Toughpower GT 850W, all sat in the $50 to $100 tier when we checked.
What to Look for in Quiet Power Supplies
Key buying criteria so you get the right fit the first time.
Rated output across these picks
Across these 5 picks rated output spans 550W (the MONTECH Century II 550W) to 850W (the Thermaltake Toughpower GT 850W). The SAMA GT750 comes second at 750W, in the same price tier as the Thermaltake Toughpower GT 850W.
How much warranty you need
The MONTECH Century II 550W tops warranty at 10 years and the Thermaltake Toughpower GT 850W sits lowest at 5 years. Start with the MONTECH Century II 550W if warranty decides it. The SAMA GT650 White and the SAMA GT750 give no warranty figure, so 3 of 5 picks are compared here.
A 24-pin ATX power cable held in a hand Cabling
The Thermaltake Smart BM3 650W lists Semi-modular; the SAMA GT650 White, the SAMA GT750, the MONTECH Century II 550W and the Thermaltake Toughpower GT 850W list Fully modular. Settling cabling first narrows 5 picks to 4 or 1.
Setup checks
The Thermaltake Smart BM3 650W has no stated native 12V-2x6 cable; confirm the cable kit before pairing it with a 16-pin card. The SAMA GT650 White comes with a native 12V-2x6 cable, so a 16-pin card plugs in without an adapter.
A 24-pin ATX connector seen from the pin side Extras that separate them
The SAMA GT750: an ECO silent mode for low load. The MONTECH Century II 550W: a 135mm fan that can stop at low load. The Thermaltake Toughpower GT 850W: a single high-amperage 12V rail.
How to Choose Quiet Power Supplies
By priority
| Priority | Consider | Why |
|---|---|---|
| Spending as little as possible, with the SAMA GT650 White the next step up | Thermaltake Smart BM3 650W | A lower price than the SAMA GT650 White and the rest when we checked |
| Buyers who want ECO silent mode for low-load quiet | SAMA GT650 White | An ECO silent mode for low-load quiet |
| Buyers who want Japanese capacitors with an LLC and DC-DC design | SAMA GT750 | Japanese capacitors with an LLC and DC-DC design |
| Buyers who put warranty first | MONTECH Century II 550W | The longest warranty here (10 years) |
| Buyers who put rated output first | Thermaltake Toughpower GT 850W | The highest rated output here (850W) |
Scroll sideways to see every column.
Key specs side by side
The Thermaltake Toughpower GT 850W leads on rated output at 850W, ahead of the SAMA GT750 at 750W. "Not listed" marks native 12V-2x6 cable count where the Thermaltake Smart BM3 650W leaves the figure out.
| Power supplie | Wattage | Native 12V-2x6 cables | Warranty | 80 Plus rating |
|---|---|---|---|---|
| Thermaltake Smart BM3 650W | 650W | Not listed | 5 years | Bronze |
| SAMA GT650 White | 650W | 1 | Not listed | Not listed |
| SAMA GT750 | 750W | 1 | Not listed | Not listed |
| MONTECH Century II 550W | 550W | 1 | 10 years | Gold |
| Thermaltake Toughpower GT 850W | 850W | 1 | 5 years | Gold |
Scroll sideways to see every column.
Frequently Asked Questions
Is the Thermaltake Toughpower GT 850W ahead of the SAMA GT750 on rated output?
The Thermaltake Toughpower GT 850W tops rated output at 850W; the SAMA GT750 follows at 750W, 13% apart. The spread runs down to the MONTECH Century II 550W at 550W.
How does the Thermaltake Smart BM3 650W compare with the MONTECH Century II 550W on warranty?
The MONTECH Century II 550W leads at 10 years, with the Thermaltake Smart BM3 650W at 5 years. The SAMA GT650 White and the SAMA GT750 are left out of this ranking because their warranty isn't stated; 3 of 5 picks are ranked.
What does the Thermaltake Toughpower GT 850W add over the Thermaltake Smart BM3 650W?
What it brings is rated output (850W against 650W). Both sat in the $50 to $100 tier when we checked, so the gains in rated output cost little extra by tier.
Why is the Thermaltake Toughpower GT 850W our Highest Rated Output pick?
The label rests on the highest rated output here (850W). On rated output it leads the SAMA GT750, 850W against 750W, a 13% margin. It is aimed at anyone who puts rated output first.
Do the Thermaltake Smart BM3 650W and the MONTECH Century II 550W differ on 80 Plus rating?
The Thermaltake Smart BM3 650W uses bronze; the MONTECH Century II 550W and the Thermaltake Toughpower GT 850W use Gold. The SAMA GT650 White and the SAMA GT750 have no 80 Plus rating listed, so 3 of 5 picks are covered here.
Will the SAMA GT650 White work with my setup?
The SAMA GT650 White comes with a native 12V-2x6 cable, so a 16-pin card plugs in without an adapter. No depth is rated for the SAMA GT650 White, so check the maker's page against your case's PSU bay. In this guide it ranks second of 5, and fourth of 5 on rated output (650W).
Bottom Line
Our first pick is the Thermaltake Smart BM3 650W, chosen for a lower price than the SAMA GT650 White and the rest when we checked. Look at the SAMA GT650 White for an ECO silent mode for low-load quiet, the SAMA GT750 for Japanese capacitors with an LLC and DC-DC design and the MONTECH Century II 550W for the longest warranty here (10 years) if those matter more to you.
Mount the PSU fan-down over a filtered intake if the case allows it.
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About the author
PC Hardware Editor
Alex covers PC hardware, monitors, components, upgrades and peripherals for The PC Journal, with a focus on helping readers understand specifications, compatibility and meaningful product trade-offs.
Covers: Monitors, Graphics cards, Processors, PC components, Peripherals, Upgrades and compatibility
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