RTX 5090 service-node power-supply and site-power decision#

Status: Current decision record Decision date: 2026-09-23 Scope: Two Malaysian residentially hosted ComfyUI service workers built around a Ryzen 9 9950X and Zotac RTX 5090 Solid OC Commercial constraint: Bootstrapped operation; prefer simple measures with measurable availability or capital benefit Current PSU decision: Keep the Seasonic Vertex PX-1200 already owned. For the new IdealTech node, prefer the regular Corsair HX1200i if its written installed-system price saves at least RM250; otherwise use the Seasonic. The Lian Li SX1200P remains the leaner alternative if its confirmed saving reaches RM500.

Why this document exists#

The PSU decision is not about finding the largest wattage number or the longest feature list. The machines will provide a paid ComfyUI cloud service, but the company is solo and bootstrapped. The useful question is:

Which power arrangement materially reduces downtime or hardware risk without spending money on rare failure modes, unused capacity, or branding?

One existing worker already uses a Seasonic Vertex PX-1200. The second worker is being quoted as part of an IdealTech promotional bundle whose current Seasonic-based ceiling is RM38,647. The relevant build is:

Ryzen 9 9950X
Zotac RTX 5090 Solid OC, 575 W board power
64 GB DDR5
2x Samsung 9100 Pro 2 TB in RAID 0 for disposable model cache
1x Kioxia 1 TB chipset-connected system drive
360 mm AIO, pump and eight case fans
Lian Li O11 Vision case

The storage and PCIe decisions are documented separately in the complete hardware decision. This record covers the PSU, the incoming electrical supply, and the UPS decision.

Decision in one page#

1. 1200 W remains the correct capacity class. Zotac specifies 575 W for the GPU and recommends a 1000 W system PSU. A good 1000 W unit can run the machine; 1200 W adds reasonable sustained-load, thermal, aging, and future CPU-concurrency margin. A 1500-1600 W label adds no ComfyUI performance and is not additional surge or outage protection.
2. Do not replace an already-owned Vertex PX-1200. It is a high-quality, independently tested PSU. A replacement would spend money and create downtime without improving throughput or materially changing risk.
3. For a new purchase, the regular Corsair HX1200i is the best same-tier value in the 2026-09-22 list. At RM1,389 it is RM311 below the RM1,700 Vertex, while independent 230 V results are competitive or better in efficiency while improving measured average noise and load regulation with essentially equal ripple. It gives up 1.4 ms of AC-loss-to-PWR_OK time and two years of stated warranty. Neither difference is likely to matter during the useful life of this node.
4. Use a price gate because package prices can differ from component-list prices. Select the regular HX1200i if the final installed-system quote is at least RM250 below the Vertex and confirms the exact ATX 3.1/PCIe 5.1 revision, supplied 600 W 12V-2x6 GPU cable, and ten-year Malaysian warranty. Below RM250, retain the Vertex for consistency with the first worker.
5. The Lian Li SX1200P is the acceptable cost-first option, not a dangerous PSU. Use it if the actual package saves at least RM500 against the Vertex and the exact black SX1200P and local ten-year warranty are confirmed. The lab result is electrically suitable, but it is materially noisier and has higher ripple than the two premium choices.
6. Do not buy a PSU on an unsubstantiated reliability story. No statistically useful field-failure data were found for these exact revisions. A single review sample, component inspection, certification, and warranty are useful screening evidence, not proof that one model fails less often in this deployment.
7. Site protection has higher leverage than moving between good PSUs. Use one properly installed, dedicated circuit per worker, sound earthing, correctly coordinated breaker and residual-current protection, and a switchboard surge-protection device. Log power quality before buying UPS capacity.
8. Do not buy two large UPS units merely to regulate normal Malaysian mains. Add them when measured interruptions, recovery labor, lost jobs, or customer commitments justify the ownership cost.

Capacity: why 1200 W, not 1000 W or 1600 W#

The Zotac RTX 5090 Solid OC specification states 575 W maximum power and recommends a 1000 W system supply. The included Antec GSK1000 therefore meets the vendor floor. It is not automatically unsafe or incapable.

This worker also has a high-end CPU, three NVMe drives, a pump, memory, motherboard conversion losses, and many fans. Normal ComfyUI traces do not fully load the CPU and GPU simultaneously, but future preprocessing or concurrent jobs might. Moving to 1200 W provides 200 W of useful margin and keeps normal operation away from the supply's upper edge. ATX 3.1 power-excursion compliance is more relevant than purchasing a large nameplate solely to absorb brief GPU excursions.

A 1500 W or 1600 W PSU does not force the machine to consume that power, but the extra capacity does not:

• make the RTX 5090 faster;
• improve PCIe or storage performance;
• condition bad building voltage;
• absorb a lightning event that the installation and SPD do not control; or
• keep the machine running during a grid outage.

The capacity may be harmless when unusually cheap, but it is not a protection feature and should receive no economic credit for this one-GPU build.

Price comparison#

Prices below come from the local IdealTech extraction dated 2026-09-22. The promotion includes an RM799 Antec GSK1000. Package totals apply the list-price difference to that included unit and are therefore provisional until IdealTech supplies a written installed-system quote.

The RM38,337 Corsair total is RM310 rather than RM311 below the quoted Seasonic total because IdealTech rounded the Seasonic substitution from its RM901 list delta to RM900.

The whole-system percentage can be misleading in either direction. RM311 is only about 0.8% of a RM38.6k node, but a bootstrapped company should still keep it when doing so sacrifices no useful capability. On the other hand, delaying a deployable node, accepting an unclear revision, or giving up a valid local warranty to recover RM311 would be false economy.

Independent 230 V evidence#

The following results are from Cybenetics' public 230 V reports. Lower ripple, regulation percentage, noise, and inrush are generally preferable; longer hold-up is preferable; a 200% transient voltage closer to 12 V is preferable. These values should not be combined into an invented reliability score. Every shortlisted unit passed its applicable test regime, and several differences are operationally insignificant.

Important limitations:

• The current Seasonic Vertex product page specifies ATX 3.1, PCIe 5.1, native 12V-2x6, a 12-year warranty, and a 160 mm enclosure. The Cybenetics sample was an earlier ATX 3.0 revision received in June 2024. Its measurements are useful platform evidence but must not be presented as a test of every current retail revision.
• The current Corsair HX1200i page specifies ATX 3.1/PCIe 5.1, an included 12V-2x6 cable, 105 °C Japanese electrolytic capacitors, a ten-year warranty, and a 200 mm enclosure. Its monitoring software is not required for operation. The worker runs Linux, so Windows-oriented iCUE telemetry receives no purchasing value unless a supported monitoring path is demonstrated.
• The Corsair HX1500i is also ATX 3.1/PCIe 5.1 with a ten-year warranty, but its 300 W of additional capacity is unused by this design. Its specified 200-240 V input is compatible with Malaysian mains but less universal than the HX1200i's 100-240 V range.
• ASUS specifies ATX 3.1, native 12V-2x6, a ten-year warranty, and a compact 160 mm enclosure for the ROG Strix 1200P. Its independent report also measured 151.7 A inrush at 230 V. It remains a capable supply, but there is no reason to pay RM150 over the HX1200i for this machine.
• The current Prime TX-1600 Noctua Edition is ATX 3.1/PCIe 5.1, 210 mm long, Titanium rated, and warranted for 12 years. Its nearest public platform results are excellent, but it costs RM610 more than the HX1200i and buys silence and unused capacity rather than availability. The RTX 5090 and case cooling also limit the value of a quieter PSU under full compute.
• The O11 Vision officially supports ATX PSUs under 232 mm, so the 200-210 mm alternatives fit on paper. The shorter 160 mm Vertex or ASUS still leaves more cable-management room. Fit must include cable bend radius, not only the metal PSU body.

What is and is not “better value”#

Corsair HX1200i: yes, at the current list spread#

This is the direct answer to the same-price-range question. The regular HX1200i has the same useful 1200 W capacity, Platinum class, current ATX/PCIe support, a supplied direct GPU cable, premium component claim, comprehensive protections, and a long warranty. The independent sample is quieter, has essentially identical full-load 12 V ripple, and regulates 12 V more tightly than the tested Vertex. It is RM311 cheaper.

The Vertex has meaningful but small advantages: two more warranty years, a 40 mm shorter body, 1.4 ms more AC-loss-to-PWR_OK time in the compared samples, and consistency with the first node. Those advantages are worth a modest premium, not an unlimited one. RM250 is the decision boundary:

• HX1200i at least RM250 cheaper, all-in: choose HX1200i for the new node.
• Difference below RM250: choose Vertex for commonality and the longer warranty.
• Vertex already installed or owned: keep it; do not create a replacement transaction.

The RM250 line is an operating rule, not a physical law. It prevents revisiting the decision for a RM50-100 quote movement while still capturing the present meaningful saving.

Corsair HX1500i: good hardware, weaker system value#

At RM1,579, the regular HX1500i is RM121 cheaper than the Vertex and has excellent measured ripple. It is therefore better specification per ringgit than the Vertex. It is not the best purchase for this node, because the HX1200i is another RM190 cheaper and already supplies all required capacity. The 1500 W label does not reduce grid risk or produce revenue. Buy it only if its live installed price is no higher than the HX1200i, or if a later configuration genuinely needs more than 1200 W.

ASUS and Seasonic Prime: no economic case here#

The ASUS Strix is competent but lands between the HX1200i and Vertex without producing a corresponding benefit. The Prime TX-1600 Noctua is an enthusiast/workstation luxury: very high efficiency, low noise, premium construction, and a long warranty, but no measurable workload or availability return in this node. Neither is the 80/20 choice.

Lian Li SX1200P: best capital efficiency, with cost-first trade-offs#

The SX1200P saves a provisional RM620 against the Vertex and RM310 against the HX1200i. Its measured output is suitable, and its current specification includes ATX 3.1/PCIe 5.1, 12V-2x6, operation at full load up to 50 °C, and a ten-year warranty. Its principal measured compromises are noise and higher full-load ripple, not evidence that it will damage the machine.

Choose it when conserving the additional RM310 matters more than premium acoustics and component margin. The regular HX1200i remains the balanced middle: it removes roughly half of the Vertex premium while keeping the premium unit's measured ripple and improving measured noise.

Reliability: what can honestly be concluded#

There is no evidence here that paying RM1,700 rather than RM1,389 produces a quantifiable reduction in annual failure probability. Manufacturer reputation, internal component selection, electrical measurements, and a 12-year warranty are positive signals. They are not a population failure-rate study under Malaysian heat, dust, voltage, and 24/7 GPU duty.

All serious candidates implement over-voltage, under-voltage, over-current, over-power, over-temperature, and short-circuit protection. Once a PSU is well designed, within specification, correctly sized, and used with its own fully seated cable, the next RM300-600 buys diminishing margins. It cannot economically insure the rest of the RM38k machine against every upstream or downstream failure.

Practical reliability controls are:

• use only the modular cables supplied for that exact PSU; never mix Seasonic, Corsair, Lian Li, or ASUS modular cables even when the plugs appear to fit;
• use the PSU-supplied direct 12V-2x6 GPU lead without the GPU's multi-connector adapter, seat it completely, avoid severe bends near the plug, and inspect it after transport;
• keep intake air and the PSU dust path clean and maintain reasonable room temperature;
• record model, part number, serial number, revision, invoice, and warranty owner;
• keep jobs retryable and the host reproducible so a failed node is an inconvenience rather than data loss; and
• when the fleet grows enough that downtime costs more than idle inventory, hold one known-compatible spare PSU and its unopened cable set. A shared spare across three or more standardized nodes will usually buy more availability than moving from one already-good premium PSU to another.

Incoming power: the higher-leverage protection layer#

Malaysia's declared low-voltage service is 230 V single-phase or 400 V three-phase. A domestic service is normally described as single-phase two-wire or three-phase four-wire, not “two-phase.” If two circuits are placed on different phases of a three-phase board, each PC remains connected phase-to-neutral at about 230 V; it must not be connected phase-to-phase at about 400 V.

One direct branch from the main distribution board to each machine is sensible. It reduces nuisance interaction with unrelated appliances but does not isolate the workers from the common incoming supply, neutral, earth, lightning exposure, or a whole-site outage. A Malaysian licensed electrical contractor should provide and test:

• one labelled final circuit per worker with no unrelated outlets or loads;
• correctly selected over-current and 30 mA residual-current protection, arranged so one worker fault does not unnecessarily disconnect the other;
• polarity, protective-earth continuity, earth-loop performance, and RCD/RCBO trip verification;
• a properly selected and earthed surge-protection device at the distribution board;
• a suitable outlet or isolator for the actual PSU/UPS input, with no daisy-chained strips or improvised adapters; and
• branch energy/power-quality logging for voltage range, interruptions, and peak current under real loads.

The relevant primary references are the Malaysian Energy Commission's residential wiring guide and TNB's supply description.

If the property later moves to three-phase service, distribute the two 230 V worker circuits across phases as part of balancing the whole site. That does not require different PC PSUs. The upgrade should be driven by measured whole-premises maximum demand, cooling, and planned node count—not by the existence of two PCs.

UPS decision#

A UPS can bridge a short interruption, provide automatic voltage regulation, and give Linux time to drain jobs or shut down. It does not replace correct earthing or surge protection, and batteries are consumables.

Do not use a common 1500 VA/900 W desktop UPS: its watt limit may be below a heavily loaded worker even if the VA label looks large. A reasonable per-node starting class is roughly 2200 VA with at least 1800 W continuous output, pure-sine output, AVR, USB or network shutdown, and replaceable batteries. The Eaton 5PX 2200i G2 is a reference design, not a mandatory model. A recent M-Link price of RM3,790 each means two units cost RM7,580 before batteries and conversion losses—about 9.8% of two RM38,647 nodes.

That purchase is not justified merely by fear of a rare event. Use this sequence:

1. Install and test the dedicated circuits, residual-current protection, earthing, and switchboard SPD.
2. Make the OS and service reproducible; keep durable data off the RAID 0 model cache; make jobs retryable.
3. Log at least 30 days of voltage, sag, swell, and interruption data, including storms.
4. Record actual recovery labor, failed jobs, customer impact, and lost gross margin from every event.
5. Buy one appropriately sized UPS per worker when expected interruption cost or service commitments exceed the monthly ownership cost. Protect the ONT, router, and switch as well, because an online server without its network path has little service value.

A central online double-conversion UPS introduces continuous loss, noise, distribution work, and a shared failure point. Revisit it when this becomes a real equipment room with several workers or logging proves the supply is persistently out of tolerance. It is not the current 80/20 answer.

Procurement instruction#

Ask IdealTech for one written table showing the final installed-system price, exact part number/revision, included 600 W 12V-2x6 GPU cable, stock status, and Malaysian warranty owner for:

1. Corsair HX1200i regular ATX 3.1/PCIe 5.1;
2. Seasonic Vertex PX-1200 current ATX 3.1/PCIe 5.1 revision; and
3. Lian Li SX1200P black.

Then choose the operating preference and apply its gate without another open-ended brand discussion:

Already own a Vertex PX-1200?
└─ Yes: keep it.

Buying the second node?
├─ Balanced preference
│  ├─ HX1200i saves >= RM250 vs Vertex, with exact revision and warranty: choose HX1200i.
│  └─ Otherwise: choose Vertex PX-1200.
└─ Cost-first preference
   ├─ SX1200P saves >= RM500 vs Vertex, with exact SKU and warranty: choose SX1200P.
   └─ Otherwise: apply the balanced rule above.

Do not accept a model-family name alone. The invoice and build record must identify the actual SKU and revision, and the builder must use only that unit's bundled cables.