CoolMax CTG-850 850W Power Supply

Today I’m taking a look at the CoolMax CTG-850. I was looking at the CTG-1000, but it was making an annoying ringing-buzzing noise and then quit working in the middle of testing. It wasn’t overloaded at all, so I’m sure it was just a defective unit (happens all the time. No big deal.) But I can’t test something that doesn’t work, so I grabbed this back up 850W unit instead.

PROD LINK: CoolMax’s Current Offerings
PRICE: $299.99 @ NewEgg
Price is at the time of testing!

This CoolMax is sold under the “Green Power” product line. What makes this CoolMax “green” is the fact that it’s RoHS compliant. This means that the power supply, accessories and packing material contain no hazardous materials. No lead in the solder. No HCFC’s in the plastic. No Azo Dye compounds.

Coolmax CTG-850

I think this is all fine and dandy. But something that bears the word “green” should also be efficient and quiet. Today we’ll see if this power supply meets MY definition of the term “green.”

Coolmax CTG-850

The CTG-850 comes with many cables and all of them are very nicely sleeved. The 24-pin ATX has a breakaway for 20-pin motherboards and there are separate 4-pin and 8-pin connector.

CTG-850 850W – Cabling
Type of connector:
Fixed Cables
ATX connector 20+4
2 x 2 12V connectors 1
2 x 3 PCI-e 2
8-pin Xeon/EPS connector 1
6-pin Xeon/AUX connector 0
5.25″ Drive connectors 8
3.5″ Drive connectors 2
SATA Drive power connectors 4
Fan only connectors (thermostatically controlled 12V only) 0

Coolmax CTG-850

The CoolMax CTG-850 has four 12V rails. I’ll get to how the rails are split up later, but first, let’s have a look at the label…

Coolmax CTG-850

CTG-850 850W – 115V – DC Output
DC Output +3.3V +5V +12V1 +12V2 +12V3 +12V4 -12V +5VSB
30A 30A 18A 18A 18A 18A 0.5A 3A
Max Power @ ?°C 180W 650W 6W 15W

Err… Wait… I thought this was an 850W power supply. Well, it is. Unlike some companies that would just give you the 230V input specifications for the power supply (which are bound to be higher since the input amperage is half what it would be in the US with 115V input), CoolMax gives us ratings for both 115V and 230V input.

Below is what the PSU does with 230V input…

CTG-850 850W – 230V – DC Output
DC Output +3.3V +5V +12V1 +12V2 +12V3 +12V4 -12V +5VSB
30A 35A 18A 18A 18A 18A 0.5A 3A
Max Power @ ?°C 190W 750W 6W 15W
829W 21W

For reference, I want to also include a photo of the 1000W unit. I know how hard it is to find specs when you’re shopping for something online. It’s not often the vendor shows what all the rails are, what they do or their combined wattage capability. Note the 230V input table on the top and the 115~230V input table on the bottom.

Coolmax CTG-850

As you can see, the CTG-1000 has 100 more watts on the 12V rail and 90 more on the 3.3V and 5V combined than the CTG-850.

To figure out what rails go where CoolMax gives you a diagram of the connectors and where they all go and the 12V wires are all color coded with a stripe. No stripe for +12V1, black stripe for +12V2, blue stripe for +12V3 and green stripe for +12V4.

Now here’s a pisser… Everything is on +12V4.

Okay… maybe not EVERYTHING is on the +12V4 rail. But all of the peripheral connectors, one of the PCI-e connectors and the 4-pin ATX+12V connector are all on +12V4. The only thing on +12V3 is the two 12V leads that feed the power to the board via the main ATX cable. The 8-pin EPS uses +12V1 and 12V2 and the other PCI-e connector uses +12V1.

Okay… Let’s try to figure this out logically. I’d want to use the PCI-e connector that’s on +12V1 and figure out a way to only use the two +12V2 wires on the 8-pin EPS.

How you’re going to go about doing that, I don’t know.

But for the load tests, I made sure to put the bulk of the load on +12V4 where it would be if you couldn’t figure out how to only have the CPU on +12V2 and the PCI-e on +12V1. Maybe we should cut off the 4-pin ATX+12V altogether…

Here are some photos of the pages of the manual that show the break down of what connectors go on what rails…

Coolmax CTG-850

Coolmax CTG-850

Coolmax CTG-850