Older model vs new model PSU

Question

I have a Corsair AX760 Watt PSU which is still new in the box but is an older model. So it was never used. It was meant to be build in a high end gaming PC but that never happened. I see that this one is still available in some shops but I wonder how the price relates to the quality after three years.

Which new generation power supply will be a mentionable replacement? Like the old model it is for a high end gaming PC too but should meet the requirements/standards for a modern gaming PC (see below). If new models have some benefits over this older one, what are those benefits and is it worth it spending the extra money while I have this unused PSU?

Some background: I expect to build a new PC somewhere in October just for gaming, including Core i5 or i7, gaming motherboard, DDR4 memory, higher end graphics card and SSD (that's all it will contain). Everything I don't have to buy can be spend on the GPU hence my question. A complementary question: The old model was intended to power two graphics cards, I'm not sure if I'm going that route this time but if I do would that influence the answer? Take into account SLI and Crossfire as I've not made any decision yet what to buy.

Answer 1

As long as you are happy with 80+ Platinum and the power envelope, there have been no significant improvements in power supply technology over the past few years. A quality PSU is a quality PSU. If it's been sat in a box, it won't have degraded, as it would have under use (PSU calculators use a 10% per year worst case in their analysis, generally you get better than that though).

The bottom line with a PSU is how much power it can provide, and how efficiently it provides it. The AX line was top of Corsairs range, just as the AXi line is now. The AXi switches analogue for digital regulation, but all that really adds is the ability to monitor/adjust PSU parameters from software, it doesn't inherently make the PSU more powerful or more efficient.

I would suggest that you only upgrade if:

• You need a higher power envelope for your new rig (unlikely if you are going for a recent 14nm CPU / 16nm GPU combination, especially if your original system was spec'd for dual 28nm era GPUs).
• You want the higher power efficiently of 80+ Titanium (unlikely to be economic unless electricity prices are very high where you live).
• You want to tinker with or monitor PSU parameters live as your system is running (doesn't seem like it is worth the expense).

Answer 2

The old one is going to be just fine; it has not degraded and PSU technology has not changed significantly in the past 3 years.

Aside from my own personal experience with pulling out heavily used and abused OEM PSUs from computers discarded into trash heaps for fun (yes, I'm that guy), there don't seem to be that many good studies of the reasons PSUs decay. There are many anecdotal discussions which mirror my own experiences to greater/lesser degrees: https://www.reddit.com/r/pcmasterrace/comments/31j95k/brothers_how_long_does_a_psu_typically_last/, but generally what this comes down to is so-called "common sense."

The PSU is fundamentally a very robust bit of solid state technology save everything except the fan(s). The fan is, because it is a mechanical part, the single most likely point of failure. Capacitors and such age over time, reducing their efficiency and tolerance, but this is a slow process with good units and even (usually) with bad old OEM units. The only other thing I know of which is KNOWN to degrade PSU technology is heat, which it would not experience sitting in storage unless it was stored in a very hot place like an attic in Arizona or something. NASA has some documentation on how they test for MTBF in solid-state electrical systems, and you can see from their methodology that heat and electrical current are the real threats to aged components.

As for the technology advancing, the best way to prove this to you is simply to refer you to sites like Newegg, Amazon, Directron, or similar, because you will see all the perks of your PSU are still being advertised as perks on modern PSUs. There is really no fundamental difference.