The advice that wastes money
Here's a story familiar to anyone who's built a PC in Australia: you ask a mate or search a forum for PSU recommendations, and someone tells you to get 850W "just to be safe." You're building a mid-range gaming rig. You'll never draw more than 400W. But the advice sounds reasonable — more headroom, right? — so you pay for it.
That extra wattage costs you twice: once at the register, and once at the power point. A PSU running at 20% load operates at its worst efficiency. The unused watts don't make your PC faster or more stable. They're dead capacity.
Here's how to actually size one.
What your PC draws at load
A typical home or office build — Ryzen 5 or Core i5, no dedicated GPU or a modest one, two drives and some case fans — runs under 200W. A mid-range gaming rig with a current GPU (RTX 4060, RX 7600) peaks around 280–350W under load. A higher-end build (RTX 4070 Ti, Ryzen 9) might hit 400–450W in a demanding game.
The important part: PSU wattage is a ceiling, not a constant draw. Your components take what they need. A 650W PSU powering a 300W system is drawing 300W — the other 350W simply isn't used.
The sensible rule: estimate your peak load, then add 20–30% headroom.
What 80 Plus actually means
Every PSU box has an 80 Plus badge. These are efficiency ratings — what percentage of the power drawn from the wall reaches your components. The rest leaves as heat.
| Rating | Efficiency at 50% load | What this means for you |
|---|---|---|
| 80 Plus White | 80% | Entry level — fine for a budget light-use build |
| 80 Plus Bronze | 85% | The sweet spot; pays for itself over time |
| 80 Plus Gold | 90% | Worth it for a PC on eight or more hours a day |
| 80 Plus Platinum | 92%+ | Diminishing returns for most home users |
For a gaming PC used a few hours an evening, Bronze is the practical choice. Gold makes sense for a workstation or home server running all day — the electricity savings genuinely add up over a year in Australian conditions.
Which wattage to actually buy
400W: office and HTPC builds with no discrete GPU. The Fortrek Black Hawk 400W 80 Plus White ATX PSU covers this range — reliable power for everyday machines without paying for wattage you'll never use. 500W: the sweet spot for a Ryzen 5 or Core i5 with a mainstream gaming GPU. Both the Fortrek Crusader 500W ATX PSU and the Fortrek Black Hawk 500W 80 Plus Bronze land here — enough headroom for a complete mid-range gaming build with drives and fans. The Bronze model is the pick if your rig runs for long sessions. 650W: when your GPU is in the RTX 4070 class or above, or you're planning a future upgrade to a more power-hungry card. The Fortrek Black Hawk 650W 80 Plus Gaming PSU is the most common choice here — a 120mm silent fan keeps noise low under heavy gaming load, and the headroom means the PSU never strains. 700W+: reserved for flagship GPU builds (RTX 4080, 4090) and dual-GPU workstations. For anything else, you're paying for capacity the system won't touch.The thing most guides leave out: form factor
ATX is the standard PSU size for mid-tower and full-tower cases, which is what most Australian home builds use. But before ordering, confirm your case actually takes an ATX unit. The Fortrek Holt Mid-Tower ATX Case is designed for standard ATX PSUs. Compact mini-ITX cases use SFX or SFX-L — an ATX unit simply won't fit regardless of wattage.
Two other things worth knowing: the PSU sits at the bottom-rear of most modern cases and pulls cool air from below — keep the intake vent off carpet, and don't stuff the PC into a sealed cabinet. Heat is what shortens power supplies; airflow is the fix.
Quick sizing guide
| Build type | Recommended wattage | 80 Plus rating |
|---|---|---|
| Office PC / HTPC, no discrete GPU | 400W | White |
| Mid-range gaming (RX 7600, RTX 4060) | 500W | Bronze |
| High-end gaming (RTX 4070 Ti, RX 7900) | 650W | Bronze or Gold |
| Flagship GPU (RTX 4080, 4090) | 750W+ | Gold |
