Can a PSU affect performance?

General Forums Off-topic Chat
1

Not directly related to Blender, but noticeable. I’ve been a self-builder of my main rig for many years (in fact, since I ripped my Amiga 1200 apart and stuck it in a tower with an '060 board, gfx card, IDE etc. - moved on since then to x86). Now I tend to do incremental upgrades, with a major upgrade when I feel I need it. The last major upgrade was around 2 years ago when I got a new MB, CPU (Ryzen 7 1800x) and RAM.

I’ve had a very intermittent issue with boot (rare, but when it happened it was a pain), when the beep codes suggested no VGA adapter found. This was originally a GTX 1060, but that has recently been replaced with a 1070 after the 1060 gave up the ghost, so I’m ruling out a GPU problem.

The MB, RAM and CPU were brand new, so I’m ruling those out, too.

I had a Corsair 650W semi-modular PSU, which I suspect I was pushing to the limit. I have 5 drives (3 spinners and 2 SSD) as well as an optical drive in this system, and I’m figuring that I was just on the threshold of what the PSU could handle.

Yesterday, I got myself a Corsair 750W (I would have got bigger, but at today’s prices, even this cost the best part of £100), and have fitted it this morning.

No issues, but the PC “feels” generally snappier, and a re-render of on an existing, unmodified scene in Blender completed slightly faster.

So, whilst it sounds counter to logic, can a PSU affect performance?

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it should not, lack of power should only affect stability.

3

you would be surprised what performance technology in GPU’s has come down to… In certain circumstances an array of chips can be deactivated by the responsible controller to only run resources which are available… so if your PSU has a fluctuation going on (such as from a very low end PSU), your hardware might take this into consideration and run at lower performance…

edit: In fact I have had this with a Radeon Card before on a low quality 500W PSU… it started buzzing (sound of the coil inside the PSU , not very loud, but you could hear it… working hard) as the card and CPU were sucking away like crazy… heating up the chipset, which lead to slightly noticeable drop in performance .

4

I wasn’t aware of that, its surprising it can maintain stability in that situation. You’d have expected to get a situation where the hardware was being under-volted.