The cost of entry for an ATX 3.1 PSU has just nosedived, as Thermaltake has just launched a new range of PC power supplies with prices that start from just $49.99. The new Thermaltake Smart BX3 Bronze lineup is marketed as ATX 3.1 ready, and comes in 550W, 650W, and 750W flavors. What’s the catch? That all depends on what cables you need.
When you’re looking for the best power supply for your needs, the ATX 3.0 spec has been a big pull over the last couple of years, especially if you own a top-end Nvidia GPU, such as the RTX 4090. However, PSUs that meet the ATX 3.0 spec often demand hefty premiums well above the $100 mark, so you might expect an ATX 3.1 model to cost even more. How has Thermaltake got the price of these new power supplies down to just $49.99?
The key here is that you don’t have to include every big new feature included in the ATX 3.1 spec to get an “ATX 3.1” ready badge. For example, one key part of the ATX 3.1 spec is the move from the ATX 3.0 spec’s infamously melty 12VHPWR cable to the new 12V-6×6 standard, with longer conductor terminals and shorter sensing pins.
However, there’s no 16-pin 12V cable of any kind on these new Thermaltake PSUs – you just get the usual pair of 6+2-pin PCIe cables. That’s fine if your graphics card uses standard PCIe power connectors, but you’ll need an adaptor to plug a lot of Nvidia cards, such as the new RTX 4070 Super, into one of these PSUs (and make sure it’s connected firmly). Sadly, another cost-saving measure is that these PSUs also have non-modular, captive cabling, although the cables are at least flat to help with cable routing.
What you do get, though, is plenty of headroom for GPU power surges. The power draw of the latest GPUs can sometimes momentarily surge well above usual during high loads, and the ATX 3.1 spec now enables your motherboard’s PCIe slot to draw a large amount of extra power for a short amount of time (0.1ms) to keep everything ticking along. Thermaltake says that its “Smart BX3 series is fully compatible with ATX 3.1 specifications which supports up to 200% power excursion,” and also claims that it offers 3x the usual headroom for GPU power surges specifically.
The new PSUs are also 80 Plus Bronze certified, which means each PSU needs to have an efficiency of at least 82% at 20% load, 85% at 50% load, and 82% at 100% load (when using a voltage of 115V). Good efficiency basically means that more of your electricity is being used to power your components, rather than being wasted, and while the 80 Plus Bronze spec isn’t as efficient as the 80 Plus Gold, Platinum, and Titanium PSUs at the top end of the scale, it’s still good enough for most scenarios, and it enables you to save a lot of money on your initial build.
Other features of the new PSUs include a 120mm fluid bearing fan, which switches off at loads under 20%, and you get a decent five-year warranty as well. The new power supplies feature a single 12V-rail design for your CPU and graphics card, with the 750W unit having a maximum current of 62.5A. The Thermaltake Smart BX3 Bronze price is $49.99 for the 550W model, $59.99 for the 650W unit, and $64.99 for the 750W option.
If you’re looking for a PSU so you can build a new PC, make sure you check out our full guide to the best gaming CPU, as well as our best graphics card guide.