I bought an HP Omen 45L prebuilt without its original graphics card because I already own an RTX 3080, which uses two 8-pin PCIe power connectors. The system uses a DPS-1200AB-26 A power supply with a non-modular wiring setup, and the only available GPU power lead is a 12VHPWR connector. HP lists the power supply as ATX 3.0 and PCIe 5.0 compliant. Would it be safe to use a 12VHPWR female-to-dual-8-pin PCIe adapter, or could the adapter or connector overheat and damage the graphics card?
3 Answers
The important detail is the 12VHPWR cable's power rating and whether it is genuinely compatible with that HP power supply. These connectors can be configured for different limits, such as 150 W, 300 W, 450 W, or 600 W. Since the original card was a much higher-power RTX 5090, the system's cable should have enough capacity for a 3080, but verify the ratings and pinout before connecting anything. A cable made specifically for the DPS-1200AB-26 A would be preferable to a generic adapter.
It would probably work, especially since an RTX 3080 draws considerably less power than the RTX 5090 that originally came in the system. However, 12VHPWR connectors have had overheating and melting problems when they are not fully inserted or the cable is sharply bent. I would only use an adapter specifically rated for the required wattage and intended for this type of PSU, not a random cable. Make sure the connector is fully seated and has plenty of clearance from the side panel.
Personally, I would avoid adding an adapter to a connector type that already has a history of connection-related failures. It may be statistically likely to work, but the risk is avoidable if you can obtain the correct HP-compatible PCIe cable or replace the power supply with one that has standard modular PCIe outputs. Do not assume that cables from different modular power supplies are interchangeable, even if the plugs look identical.
The original GPU was an RTX 5090, so its power requirements should be much higher than those of my RTX 3080.