CoolerMaster is one of those brands that everyone respects, but when you actually look closely many of their products (though not all) have an air of iffiness about them. In particular, their power supplies.
Real Power Pro 850W - 1250W (End of Life (EOL)):
Let's start with the good. The Real Power Pro line of power supplies was CoolerMaster's premium branding, Enhance units with all-around excellent performance. These were very good power supplies and if you can find one I'll generally recommend it if the price is right. Speaking of, the only reason these units didn't find more recommendations was because of slightly high prices compared to competition, making them poor bang for the buck.
Real Power Pro 550W - 750W (EOL):
The lower-wattage continuation of the Real Power Pro line, these units were built by ACBel rather than Enhance. Though ACBel is generally lower regarded as an OEM than Enhance is, these power supplies still managed to deliver very good performance. Again, though, the killer was price, with these being priced higher than the competition.
Ultimate Circuit Protection (UCP) 700W - 1100W (EOL):
These were also high-end ACBel units. Their gimmick was an LED that would come on when the OVP/OCP/OPP/SCP/UVP/OTP were tripped. Like their cousins the Real Power Pro line, the UCP series delivered clean power with good voltage regulation. However, the +12V ripple suppression was merely adequate. Furthermore, no testing was done on the 1100W unit, so its performance is unknown. Generally, however, the UCP series was a good choice.
So far we've looked at two different series, both of them quite good. However, you may have noticed the "EOL" tag. EOL means "End of Life", which means that the product is no longer made or distributed. Thus any Real Power Pro or UCP power supply you find for sale is either surplus stock, refurbished, or used. Thus they're very hard to come by new in box. So let's look at what you're likely to find on store shelves, CoolerMaster's current line-up of power supplies.
eXtreme Power Plus 400W - 650W:
These are garbage, ACBel's cheapest, shoddiest units, and they're everywhere. Not one of the EPP line can deliver more than 2/3s of its rated wattage. Even at their "real" ratings they're poor, barely keeping in spec in most cases. I place the eXtreme Power lineup only one tier above generic units from Leadman or Linkworld or Sun Pro. No one should buy these. However, they're one of CoolerMaster's best selling lineups, because they're so cheap and they're stacked a score high in every retail store in the country. I've been into a Microcenter that had a literal 5 foot pyramid of eXtreme Power Plus 500W units; a shame I didn't have my camera. Don't let the CoolerMaster brand name fool you, these are the types of power supplies that you hear horror stories about.
Elite Power 400W - 460W:
The Elite Power PSUs are mediocre FSP half-bridge units. The 400W is mediocre, but acceptable as an emergency replacement or extreme budget unit. However, the 460W Elite Power is an insult. CoolerMaster took the 400W EP, changed the numbers on the label to 460W, then added $10 to the price. It's the same power supply. Ok, true, they upgraded the rectifying bridge, but since this design is secondary-side limited that had no effect on the rated wattage. The EP 460W is the same power supply as the 400W, topping out at 420W before shutting down (they didn't even change the protections settings). This is bordering on fraud.
GX 650W - 750W:
The GX series is marketed by CoolerMaster toward gamers as a budget PSU. The naming scheme is reminiscent of Corsair's "*X" nomenclature. Don't be fooled. Only the 750W model has been tested; it was found that the +3.3V ripple goes out of spec at 450W load, and the +12V goes out of spec at 550W. If you've read my articles you know that excessive ripple hinders overclocking and can damage components. Thus this is no more than a 450W power supply in real use. The 750W's current price at Newegg is $80. Seeing as how you can get a Corsair VX450 for $65 or a SeaSonic S12II Bronze 430W for $66, that gives this Seventeam-built CoolerMaster product a null value.
Silent Pro M 600W - 700W:
This is the first non-EOL PSU lineup from CoolerMaster that I can't immediately hate, surprising since it's from ACBel, who churn out the egregious EPP line. The Silent Pro M lineup has decent, if not spectacular performance and can actually keep its ripple under control, something that CoolerMaster seems to have trouble with. Unfortunately, though the marketing claims a "single, powerful +12V rail" that rail seems a bit weak considering it's rated at only 40A and 50A for the 600W and 700W versions, respectively, making them 500W and 600W power supplies under realistic load patterns. With that in mind, they cost more than better-performing units of similar wattage from Corsair and Antec, making them mostly pointless.
Silent Pro M 850W - 1000W:
The Silent Pro M850 is an FSP unit, rather than ACBel like the 600/700W units sold under the same name. Unlike its ACBel cousins it has a +12V rating of 66A, which is reasonable for its labeled wattage. The performance is actually fairly solid with good ripple suppression. However the $140 price tag isn't low enough for what you get, considering that comparable or better units from Corsair, Antec, SeaSonic, and Silverstone can all be found for the same price or cheaper. However, the 1000W version is more fairly priced at $165. These are the first non-EOL units from CoolerMaster to get my (tentative) approval.
Silent Pro Gold 800W - 1200W:
The Silent Pro Gold series mark a return to Enhance for CoolerMaster. These PSUs promise efficiency between 87% and 90% and bear the 80+ Gold badge, this being a popular marketing point in the current PSU market. However, despite bearing the 80+ badge these power supplies cannot meet 90% efficiency at 50% load under realistic temperature conditions of 40C (80+ tests at an unrealistic 23 degrees Celsius). They also have horrible ripple and poor regulation on the -12V rail (though this isn't too significant) and mediocre ripple of ~100mV on the +12V rail, which as I've said over and over this can have noticeable effects on overclocking and hardware lifetime. Note that only the 800W unit has been tested; the 1000W and 1200W may perform better. However, this is unlikely since the lower wattage units of a given platform tend to perform better than the higher wattage ones. So despite being efficient, I cannot give my recommendation to the Silent Pro Gold series.
So what have we learned? CoolerMaster is crap. Of the dozens of power supplies in their lineup, there are only four to which I can give even tentative approval, and two which are anywhere near a good value. Many of their "budget" units bear labels which are a complete fiction and are barely better than the garbage you find for free with $20 cases. Even some of their better units are labeled misleadingly, presenting a good marketing image but falling apart under actual testing.
CoolerMaster power supplies coast along on brand recognition and on the good reputation of their cases. There is no substance to most of their PSUs, only marketing fluff. I cannot recommend CoolerMaster as a brand, and if one were so inclined I would not view it as unreasonable to boycott them until they can deliver a quality product and remove the overrated garbage eXtreme Power Plus, Elite Power, and GX PSUs from store shelves.
Further Reading
Real Power Pro 850W - 1250W (End of Life (EOL)):
Let's start with the good. The Real Power Pro line of power supplies was CoolerMaster's premium branding, Enhance units with all-around excellent performance. These were very good power supplies and if you can find one I'll generally recommend it if the price is right. Speaking of, the only reason these units didn't find more recommendations was because of slightly high prices compared to competition, making them poor bang for the buck.
Real Power Pro 550W - 750W (EOL):
The lower-wattage continuation of the Real Power Pro line, these units were built by ACBel rather than Enhance. Though ACBel is generally lower regarded as an OEM than Enhance is, these power supplies still managed to deliver very good performance. Again, though, the killer was price, with these being priced higher than the competition.
Ultimate Circuit Protection (UCP) 700W - 1100W (EOL):
These were also high-end ACBel units. Their gimmick was an LED that would come on when the OVP/OCP/OPP/SCP/UVP/OTP were tripped. Like their cousins the Real Power Pro line, the UCP series delivered clean power with good voltage regulation. However, the +12V ripple suppression was merely adequate. Furthermore, no testing was done on the 1100W unit, so its performance is unknown. Generally, however, the UCP series was a good choice.
So far we've looked at two different series, both of them quite good. However, you may have noticed the "EOL" tag. EOL means "End of Life", which means that the product is no longer made or distributed. Thus any Real Power Pro or UCP power supply you find for sale is either surplus stock, refurbished, or used. Thus they're very hard to come by new in box. So let's look at what you're likely to find on store shelves, CoolerMaster's current line-up of power supplies.
eXtreme Power Plus 400W - 650W:
These are garbage, ACBel's cheapest, shoddiest units, and they're everywhere. Not one of the EPP line can deliver more than 2/3s of its rated wattage. Even at their "real" ratings they're poor, barely keeping in spec in most cases. I place the eXtreme Power lineup only one tier above generic units from Leadman or Linkworld or Sun Pro. No one should buy these. However, they're one of CoolerMaster's best selling lineups, because they're so cheap and they're stacked a score high in every retail store in the country. I've been into a Microcenter that had a literal 5 foot pyramid of eXtreme Power Plus 500W units; a shame I didn't have my camera. Don't let the CoolerMaster brand name fool you, these are the types of power supplies that you hear horror stories about.
Elite Power 400W - 460W:
The Elite Power PSUs are mediocre FSP half-bridge units. The 400W is mediocre, but acceptable as an emergency replacement or extreme budget unit. However, the 460W Elite Power is an insult. CoolerMaster took the 400W EP, changed the numbers on the label to 460W, then added $10 to the price. It's the same power supply. Ok, true, they upgraded the rectifying bridge, but since this design is secondary-side limited that had no effect on the rated wattage. The EP 460W is the same power supply as the 400W, topping out at 420W before shutting down (they didn't even change the protections settings). This is bordering on fraud.
GX 650W - 750W:
The GX series is marketed by CoolerMaster toward gamers as a budget PSU. The naming scheme is reminiscent of Corsair's "*X" nomenclature. Don't be fooled. Only the 750W model has been tested; it was found that the +3.3V ripple goes out of spec at 450W load, and the +12V goes out of spec at 550W. If you've read my articles you know that excessive ripple hinders overclocking and can damage components. Thus this is no more than a 450W power supply in real use. The 750W's current price at Newegg is $80. Seeing as how you can get a Corsair VX450 for $65 or a SeaSonic S12II Bronze 430W for $66, that gives this Seventeam-built CoolerMaster product a null value.
Silent Pro M 600W - 700W:
This is the first non-EOL PSU lineup from CoolerMaster that I can't immediately hate, surprising since it's from ACBel, who churn out the egregious EPP line. The Silent Pro M lineup has decent, if not spectacular performance and can actually keep its ripple under control, something that CoolerMaster seems to have trouble with. Unfortunately, though the marketing claims a "single, powerful +12V rail" that rail seems a bit weak considering it's rated at only 40A and 50A for the 600W and 700W versions, respectively, making them 500W and 600W power supplies under realistic load patterns. With that in mind, they cost more than better-performing units of similar wattage from Corsair and Antec, making them mostly pointless.
Silent Pro M 850W - 1000W:
The Silent Pro M850 is an FSP unit, rather than ACBel like the 600/700W units sold under the same name. Unlike its ACBel cousins it has a +12V rating of 66A, which is reasonable for its labeled wattage. The performance is actually fairly solid with good ripple suppression. However the $140 price tag isn't low enough for what you get, considering that comparable or better units from Corsair, Antec, SeaSonic, and Silverstone can all be found for the same price or cheaper. However, the 1000W version is more fairly priced at $165. These are the first non-EOL units from CoolerMaster to get my (tentative) approval.
Silent Pro Gold 800W - 1200W:
The Silent Pro Gold series mark a return to Enhance for CoolerMaster. These PSUs promise efficiency between 87% and 90% and bear the 80+ Gold badge, this being a popular marketing point in the current PSU market. However, despite bearing the 80+ badge these power supplies cannot meet 90% efficiency at 50% load under realistic temperature conditions of 40C (80+ tests at an unrealistic 23 degrees Celsius). They also have horrible ripple and poor regulation on the -12V rail (though this isn't too significant) and mediocre ripple of ~100mV on the +12V rail, which as I've said over and over this can have noticeable effects on overclocking and hardware lifetime. Note that only the 800W unit has been tested; the 1000W and 1200W may perform better. However, this is unlikely since the lower wattage units of a given platform tend to perform better than the higher wattage ones. So despite being efficient, I cannot give my recommendation to the Silent Pro Gold series.
So what have we learned? CoolerMaster is crap. Of the dozens of power supplies in their lineup, there are only four to which I can give even tentative approval, and two which are anywhere near a good value. Many of their "budget" units bear labels which are a complete fiction and are barely better than the garbage you find for free with $20 cases. Even some of their better units are labeled misleadingly, presenting a good marketing image but falling apart under actual testing.
CoolerMaster power supplies coast along on brand recognition and on the good reputation of their cases. There is no substance to most of their PSUs, only marketing fluff. I cannot recommend CoolerMaster as a brand, and if one were so inclined I would not view it as unreasonable to boycott them until they can deliver a quality product and remove the overrated garbage eXtreme Power Plus, Elite Power, and GX PSUs from store shelves.
Further Reading