Our Verdict
Pros
- Premium 105C Capacitors
- Three-sided cable routing
- Very affordable
Cons
- Not modular
Should you buy it?
Introduction, Specifications, and Pricing
Have you ever wondered if you actually need a new PSU or whether a modular one is really necessary? As for the 80 PLUS rating, I'm here to tell you both specifications will raise the price considerably. So, what happens when you remove those features? You end up with the Lian Li RBO750B ATX 3.1 PSU, available at an upfront MSRP of $69.99.
Although the RBO 750B has only an 80 PLUS Bronze rating and may not be the most efficient ATX 3.1 PSU, it has a hidden feature that, in one way, addresses the modularity issue. Therefore, let's have a look at the RBO750B from Lian Li.
Popular Now: AFTERSHOCK's $14,200 Cherry Bloom gaming PC uses titanium flowers that bloom with heat| Item | Details |
|---|---|
| Model | Lian Li RBO750B |
| Form Factor | ATX |
| Dimensions | 150x150x86 mm |
| Color | Black |
| ATX12V Version | ATX12V V3.1 |
| Fan | Hong Hao HYB fan, 135mm |
| Protections | OPP, OVP, SCP, OCP, UVP, OTP |
| Capacitor Type | Toshin Kogyo - 420V / 470µF |
| AC Input | 100 - 240 V / 10A |
| Efficiency | 80 PLUS Bronze |
| Warranty | 10 Years |
Packaging
The RBO750B comes in a standard Lian Li package: a black box with blue accents.
The back of the packaging shows ten language versions and three pictures.
Best Deals: Lian Li RB750B 750W ATX 3.1 80 Plus Bronze Power Supply
Prices last scanned 5 hours and 46 minutes ago
7 days ago: $64.99 USD
7 days ago: $69.99 USD
7 days ago: $101.92 CAD
7 days ago: $119
The included cable set for the RBO750B includes:
- M/B 20+4 Pin Main Power - 600mm
- CPU EPS 4+4 Pin (2) - 650mm
- GPU PCIe 2x8 / 6+2 Pin - 600mm + 150mm
- SATA x3 / PATA x1 - SATA 400mm/150mm + PATA 150mm
- SATA x2 / PATA x1 - SATA 400mm/150mm + PATA 150mm
- 12V-2x6 to PCIe - 100mm
- 12V-2x6(450W) - 600mm
On the packaging, Lian Li lists the RBO750B specifications, including the model number, ATX rating, 80 PLUS Bronze rating, DC cable type, dimensions, color, PFC type, input rating, and several other ratings and protections.
On the packaging, the left-hand side shows the PSU's 80 PLUS efficiency curve, rated at 80 PLUS Bronze and indicating 85% efficiency at 50% PSU load, while the right shows the fan's acoustic noise curve, with a maximum of 40 dB as advertised.
Our Latest 80 PLUS Bronze PSUs Review Coverage
The packaging has a flap that displays the AC input and DC output ratings, indicating a total output of 750 watts when operating at 100 to 240 volts AC and 10 amperes.
Frequently Asked Questions
Open a question for an answer from TweakTown's coverage of this review, or ask your own below.
What GPUs can the RBO750B’s native 12V-2x6 cable power without adapters?
How does the RBO750B’s fixed cabling affect cable management in smaller cases?
What kind of efficiency did the RBO750B achieve during testing at around 50% load?
What does ATX 3.1 mean for compatibility with newer graphics cards and power spikes?
Have a question that isn't listed here? Ask below, and TweakBot will answer it.
When we open the flap, we find Lian Li has placed the RBO750B in a clear plastic bag and surrounded it with open-cell foam; all the cabling is neatly bundled on the right-hand side, along with the C13 power cable.
Lian Li also includes a user manual, SATA/PATA connectors, the C13 power cable mentioned above, mounting screws, and a Thank-You card.
Outside the Lian Li RBO750B ATX 3.1 PSU
The sticker indicating the power input is on the underside of the RBO750B.
Lian Li incorporated cable loops into the RBO750B design to help with cable management and routing.
The cables all emerge from the same point, but using the cable Velcro straps can improve the appearance.
The back of the RBO750B has a honeycomb ventilation design, along with the standard power input and power rocker switch.
Inside the Lian Li RBO750B ATX 3.1 PSU
The hydraulic bearing fan made by Hong Hao has 11 blades, a high-sweep design, and reaches a maximum speed of 1,600 RPM at 40.1 dB.
Finally, the design uses a Helly Technology platform (more precisely, an APFC + Half-Bridge LLC + DC-to-DC topology intended for 80 PLUS Bronze designs). The bulk capacitor is a single electrolytic capacitor on the primary side (top-left position), made by Toshin Kogyo Co. and rated at 470uf at 420v. TK is also regarded as a tier 2 capacitor brand.
Installation, Testing, Finished Product, and Final Thoughts
Ryan's Test System Specifications
| Item | Details |
|---|---|
| Motherboard | MSI Z790 Project Zero Gaming Motherboard (Buy at Amazon) |
| CPU | Intel Core i5-12600K (Buy at Amazon) |
| RAM | Corsair Dominator Platinum 32GB DDR5-7200 (Buy at Amazon) |
| GPU | ZOTAC GeForce RTX 3090 Trinity (Buy at Amazon) |
| Display | Nixeus EDG 27" IPS 3840 x 2160 144Hz Ultra HD 4K (Buy at Amazon) |
| SSD | Kingston Fury Renegade 1TB (Buy at Amazon) |
| PSU | Enermax PlatiGemini 1200W 80 PLUS Platinum |
| Cooler | be quiet! Pure Rock Pro 3 (Buy at Amazon) |
| OS | Microsoft Windows 11 Pro (Buy at Amazon) |
To evaluate the Lian Li RBO750B under realistic hardware stress, we installed it into our heavy-duty AMD Ryzen 9 7950X and RTX 3090 test rig. To analyze the unit's conversion efficiency near a 50% load target (~375W DC draw), we locked the 16-core CPU to a fixed 1.12V vCore at 4.3GHz (152W average) and set the RTX 3090's power target to 40% (~140W average). With motherboard and drive power accounting for roughly 40W, internal DC power draw hit the 332W target.
The test setup underwent a continuous, almost 13-hour burn-in session using AIDA64 Engineer's System Stability Test in a controlled ambient room temperature of 17°C. System telemetry and voltage stability were recorded using HWiNFO64, GPU-Z, and CPU-Z.
At the wall outlet, a digital Kill-A-Watt P3 electrical meter measured a steady power draw averaging 375 Watts (oscillating between 372W and 377W). Calculating the ratio between total internal system DC draw and AC wall draw yields a 50% load efficiency of 88.4%. This performance significantly exceeds the official 80 PLUS Bronze requirement (85% efficiency at half-load) and nearly reaches the 80 PLUS Silver classification (89%). Furthermore, the 135mm Hong Hao fan remained surprisingly quiet throughout the entire 13-hour stress run, staying well below audible noise thresholds inside a closed PC chassis.
When evaluating budget power supplies, reviewers often have to temper expectations. Low-cost units frequently compromise on safety protections, use sub-par caps, or rely on outdated internal topographies that struggle with modern GPU transient spikes. Lian Li set out to subvert those expectations with the RBO750B ATX 3.1 PSU, attempting to deliver current-generation standards to builders working on tight margins. At a competitive $69.99 MSRP, the RBO750B hits a crucial sweet spot in the modern PC market. By stripping away non-essential luxuries like full cable modularity and expensive Gold-level certification testing, Lian Li redirected their budget toward what actually matters: internal platform stability and native next-gen connectivity.
Under the hood, the Helly Technology platform punches well above its weight class. Utilizing an Active PFC, Half-Bridge LLC Resonant Converter, and DC-to-DC step-down architecture, the electrical delivery is surprisingly modern for a Bronze-tier unit. The primary side is anchored by a single Japanese-designed Toshin Kogyo (TK) 105°C main capacitor (420V / 470µF), providing solid hold-up times and thermal endurance under heavy stress.
In real-world bench testing, the power supply far exceeded its marketing claims. Standard 80 PLUS Bronze parameters require 85% efficiency at half-load, yet the RBO750B turned in a commendable 88.4% efficiency at a 375W load target. That puts it right on the doorstep of 80 PLUS Silver efficiency, meaning less power wasted as ambient heat inside your system. Coupled with a dynamic 135mm Hong Hao fan that remained practically silent throughout our 13-hour continuous burn-in, acoustics and thermal management are non-issues.
The obvious elephant in the room with any budget power supply is the fixed cabling. Non-modular wire bundles have earned a really bad reputation over the years for creating unsightly "cable nests" inside power supply basements and blocking essential airflow channels. While hardwired cables are inherently more rigid and clutter-prone than fully modular alternatives, Lian Li devised a clever physical workaround. By strapping integrated cable-routing loops along three sides of the metal chassis, Lian Li gives builders built-in anchor points directly on the PSU housing. Combined with the provided cable straps, you can cinch down unused wires neatly against the unit, dramatically improving build aesthetics and cable routing through back-plane chassis cutouts. Additionally, the included native 450W 12V-2x6 high-power cable eliminates the need for messy, multi-adapter PCIe splitters when powering current-generation GPUs.
If you have a flexible budget, spending $30 to $50 more on a fully modular 80 PLUS Gold power supply will offer easier assembly, custom-sleeved cable compatibility, and marginal long-term energy savings on your electric bill. However, if you are building a budget-conscious gaming PC or upgrading a system where every dollar counts, putting those extra savings toward a faster graphics card or CPU delivers far more tangible real-world performance. The Lian Li RBO750B delivers rock-solid voltage stability, near-Silver conversion efficiency, silent operation, and native ATX 3.1 support at a hard-to-beat price. For budget system builders needing reliable 750W power for modern components without breaking the bank, the Lian Li RBO750B is an easy recommendation. It comfortably earns its spot on your buying shortlist.
