A systems engineer is assembling a high-performance workstation featuring a high-end CPU (… — CompTIA A+ (Core 1 & Core 2)

A systems engineer is assembling a high-performance workstation featuring a high-end CPU ( $125\text{ W}$ TDP), a flagship discrete GPU with a peak power draw of $450\text{ W}$ , multiple NVMe drives ( $30\text{ W}$ combined), and liquid cooling pumps with fans ( $45\text{ W}$ combined). The system is currently equipped with a $650\text{ W}$ power supply unit (PSU). Under full benchmarking load, the workstation instantly shuts off without generating any operating system crash logs or blue screen errors. Which of the following statements correctly explain the root cause of these shutdowns and identify the necessary power infrastructure requirements for stable operation? (Select TWO.)

The existing power supply fails to provide adequate wattage headroom to support the combined continuous component power budget and transient GPU peak power excursions, requiring a replacement rated for at least $850\text{ W}$ .Answer
The graphics card must receive dedicated auxiliary power connections via individual $+12\text{ V}$ cable runs from the PSU rather than a single daisy-chained cable split across multiple headers.Answer
C
The motherboard PCIe x16 expansion slot is defective because it fails to supply the required $450\text{ W}$ of auxiliary power directly through the motherboard bus pins.
D
The system motherboard requires an upgraded EPS12V CPU power connector configured to auto-negotiate wattage draw with the expansion bus during heavy processing workloads.

Answer

Stable operation requires replacing the power supply with a unit rated for at least

850\text{ W}

to accommodate baseline draws and GPU transient spikes, alongside powering the graphics card using independent, non-daisy-chained auxiliary

+12\text{ V}

power cables directly from the PSU.

The correct selections recognize both the quantitative wattage deficit and the physical power delivery cabling requirements. The baseline load of

650\text{ W}

leaves zero margin for efficiency loss or transient GPU power spikes on a

650\text{ W}

PSU, requiring an upgrade to an

850\text{ W}

or higher unit. Additionally, high-wattage graphics cards require independent PCIe auxiliary power cables connected directly to dedicated PSU outlets to prevent overcurrent cable failure and trips.

Step-by-Step Solution

Calculate the continuous power baseline of the workstation components.

Sum of component power draws:

125\text{ W (CPU)} + 450\text{ W (GPU)} + 30\text{ W (Storage)} + 45\text{ W (Cooling)} = 650\text{ W}

Establishing total continuous power consumption establishes the minimum theoretical load.

Apply standard industry sizing headroom (

20\%\text{--}30\%

) for efficiency and transient GPU power excursions.

650\text{ W} \times 1.25 \approx 812.5\text{ W}

, indicating a minimum recommended PSU rating of

850\text{ W}

Modern GPUs exhibit momentary power spikes above their rated TBP, triggering Over-Power Protection (OPP) on un-headroomed power supplies.

Evaluate GPU auxiliary power delivery requirements.

Since PCIe slots only provide up to

75\text{ W}

, the remaining

375\text{ W}+

must come from multiple independent PCIe 8-pin or 12VHPWR/12V-2x6 cables running from distinct PSU terminals.

Using daisy-chained splitters on a single cable trunk exceeds safe current limits per gauge wire, triggering Over-Current Protection (OCP) or overheating.

Key Concept

Power Budget Sizing and Auxiliary GPU Cabling Standards

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