Hello everyone,
I'm looking to upgrade my current setup with a 7900XTX and the manufacturer website recommends 850W at a minimum.
As the title says, I currently only possess a 750W PSU (Corsair RM750x (2021)).
Rest of the system (the parts that draw power at least):
Mainboard: Asus TUF GAMING X570-PLUS
CPU: AMD Ryzen 9 3900X
RAM: 4x8GB DDR4
Storage: 1x Samsung 990 Pro 2 TB, 1x Samsung 970 Evo 500 GB, 2x older Samsung SATA SSDs
Fans: 3x Case fans, 1x Noctua CPU cooler (forgot the exact name)
PSU: Corsair RM750x (2021)
Putting everything into PCPartpicker makes it spit out a max load of 608W, but considering that the 3900X can spike to draw up to ~145W (instead of the 105W TDP) and the 7900XTX can spike up to ~530W (instead of the 355W PCPartpicker assumes) I'd have peak loads just short of 850W...
My question now is twofold:
- How reliable is the Power Usage Limit I set in LACT enforced? If I can rely on it to keep the GPU to 355W I should (in theory) be fine, right?
- How bad is it to trigger the overdraw protection in the PSU? Obviously my PC would shut down immediately (with all that entails), but would I risk damage to components?
Thanks for any help :)
PS: I'm set on the 7900XTX, as I want the 24GB VRAM. It's quite literally the cheapest option (new, in my region) that is also a usable gaming card.
PPS: Yes, I'm going to upgrade the PSU soon. Just not now if I can avoid it. (They aren't exactly free...)
I may be able to provide some personal experience regarding the first part of the first question, "How reliable is the Power Usage Limit I set in LACT enforced?". The answer appears to be application based and I will do my best to explain.
I was having a persistent issue with my GPU PPT0 throttling during gaming sessions with a specific area in a specific game. This was the first time I had ever experienced this odd behavior which initially presented as a rapid increase in GPU fan speeds and a small loss in frame-rate. By using LACT, I was able to confirm why this was happening and the real-time data was indicating that as soon as the GPU got within about 10% of the power cap, it would start to power throttle. The crazy thing was, the 170 Watt cap would not stop the card from drawing over 190W in short bursts. By increasing the power cap to 190W, it did reduce the throttling somewhat but then my GPU was still exceeding this revised cap and I didn't see any real value in pushing the value higher.
I have a decent safety margin with a 9600X and a 9060XT using a Corsair 750e PSU. I imagine your setup has much higher peak power needs so I would suggest reducing the power cap by 10% to start and then incrementally adjusting the core voltage downwards using the undervolt option. This should allow you to achieve a stable operating level if you are careful and find the sweet spot between performance and power draw. Otherwise, getting a beefier PSU may be your safest bet.