Decent Performance; Tough Competition
The folks at Corsair know that the big money in PSUs is made from the mid-range space. So, they added a more powerful supply to the company's CS family offering up to 850W of output. That's enough to drive an enthusiast configuration with a couple of graphics cards. Nowadays, most builders keep their PSU budgets low, meaning manufacturers need affordable options in their portfolios.
The CS850M we evaluated today costs a little more than $100 dollars, so we can’t exactly call it cheap. However, that price is in line with most of Corsair's competition. For the time being, it is difficult for any company to offer 80 PLUS Gold efficiency and a semi-modular cabling with capacity approaching 1000W, and still hit a price point around $100 without seriously compromising quality.
But because of the many PSUs in this segment, Corsair needs to drop its price even more to make this specific model a stand-out. At $120, the CS850M approaches what you'd pay for much higher-end power supplies that offer better performance and longer warranty coverage.
The CS850M registers decent overall performance; it would have been much better if the platform handled transient loads more deftly. In the real world, a PC won’t subject its PSU to steady loads. Rather, levels will vary constantly according to utilization. Admittedly, our Advanced Transient Load benchmarks are based on some extreme case scenarios, but any modern PSU should be able to handle them. The CS850M managed to pass those tests successfully, but we'd like to see lower deviations on its rail, which would lead to better performance.
Our efficiency testing went much better; the CS850M yielded satisfactory load regulation results, too.
Ripple suppression on the +12V rail could be improved. Although it was excellent on the other rails, the +12V rail's performance is what matters since most PC components are powered by it. Our advice to Corsair is to sell the CS850M at a lower price, creating a larger price gap between higher-end PSUs with similar capacity.