The RM750 scores a bit lower in overall performance than the RM750x (2018), but has some notable advantages. For starters, its efficiency at light loads is impressive due to the burst-mode operation of its LLC resonant converter, which it is given the capability for by the new Champion controller with model number
CU6901V. Moreover, the RM750 supports the new standby function; if paired with a compatible mainboard, it can wake up the system within five seconds. Currently, depending on the hardware, the S3 sleep state takes from anywhere between 7–15 seconds to turn on the PC. This is a significant improvement that will make our PCs behave like mobile phones. Touch the keyboard or the mouse and the system will wake up in no time. I wish there were a similar technology to allow this for users as well.
The major downside of the RM750 is that its price is close to the higher-end model RM750x because the two significant changes I mentioned above have a high manufacturing cost according to Corsair. Despite the more affordable Hong Hua fan and the Elite caps, the price gap is small, and this can be a major issue for users who think of Japanese caps as a must-have feature. I am confident that the Elite caps and Hong Hua fan will outlive the very long warranty period Corsair provides for this product as it wouldn't have the same warranty as the RM750x otherwise. Elite caps are the best alternative to the popular Japanese brands, and so far, they have proven reliable.
The RM750 might not be as quiet as the RM750x in terms of noise output, but it is still close to 21 dB(A) noise output overall, so you can easily call it silent. It might lose in terms of noise, but wins in efficiency (90.642% vs. 90.218% overall efficiency with 230 V input).
If I had to choose my next 750 W PSU from among Corsair's offerings, I would still probably go with the RM750x given the price gap is small, mostly because I am a huge fan of the NR135L fan. The price difference should be around $20 to make me prefer the RM750 over the RMx model of equivalent capacity. The first might have higher efficiency and support the new standby function, but the latter comes with a better fan and only uses Japanese caps. Hopefully, Corsair will find a way to reduce the production cost of these new RM models to lower their prices to more competitive levels.