The Coomax CX-450 caught my attention when I noticed that the temperatures of my overclocked Barton system were getting higher than I’d anticipated. Below is a recount of my experiences with the Coolmax 450 watt PSU in comparison to my previous SilenX 400 PSU. So far, the Coolmax looks like a good choice for anyone who needs ample power, and quiet operation, on a tight budget.

This all started when I sold most of the parts from my previous computer and essentially started over with some refurbished parts from Newegg.com. I had purchased a GMC Trinity X21 case, when Newegg marked them down to $20 each, and recently painted the inside with Plasti Dip as discussed in another thread. For those unfamiliar with the X21, it’s a mid-sized tower with and attractive front door and the ability to accommodate up to four 80mm case fans. Unfortunately, it has a somewhat restrictive front bezel, which I believe limits the effectiveness of the case fans.

I’d kept the SilenX 400Watt PSU from my previous system. It’s still the quietest PSU I’ve ever had and it had served me well with my previous Pentium IV based system. Unfortunately, the SilenX didn’t seem to move enough air to help cool my overclocked Barton system when I added a BFG 5900 video card into the mix. I tried adding faster 80mm case fans, which made my system about as loud as your average off the shelf computer, which was totally unacceptable. I decided my options were to mod the case, modify the SilenX, or replace the SilenX with something that moved more air.

Obviously, I chose to replace the PSU with a model that included a low speed 12cm fan. Since most of my other parts were purchased at bargain bin prices, I didn’t like the idea of spending over a hundred dollars on a PSU. After reading several user comments on the Coolmax Taurus series PSUs, which often commented about how quiet they were, I decided it was worth $49.99 to see if this would be a good compromise between cooling and performance.

I tested this PSU with two video cards. The first is a refurbished Radeon 9600np made by Connect3D, which sometimes works and sometimes doesn’t. The second is a BFG 5900 VIVO. Even though both cards were built on .13 micron technology, the 5900 runs noticeably hotter than the Radeon, which makes it a good choice to see the effectiveness of the Coolmax PSU in compariston to the SilenX. All tests were conducted with a 2500+ Barton overclocked to 3200+ speeds installed in the X21 case with five low speed NMB case fans (2 intake, 2 exhaust, and 1 below the video card with a modified Zalman bracket). Aside from a coat of Plasti Dip, sound absorbing material was also installed in the case to reduce noise. Thin sound absorbing pads from CompUSA were installed on the top, bottom, and side panels. An additional 1 inch thick 6”x7” inch pad sample pad from DB Engineering was installed perpendicular to the BFG 5900 (and parallel to the side panel) to absorb most of the sound made by it’s dual fan cooler. Several runs of 3DMark 2003 were used to approximate system loads that would likely be experienced during a heavy gaming use. Below are my results.

SilenX 400 with Radeon 9600np - - Max CPU Temp 51 deg. Celsius
SilenX 400 with BFG 5900 - - - - - - Max CPU Temp 59 deg. Celsius
Coolmax 450 with Radeon 9600np- Max CPU Temp 46 deg. Celsius
Coolmax 450 with BFG 5900 - - - - Max CPU Temp 54 deg. Celsius

Overall, case temperatures have dropped by approximately 5 degrees with the Coolmax. I believe this difference more of an indication of the ineffectiveness of the SilenX in removing heat than the effectiveness of the Coolmax. I probably could have achieved similar results, or better, with a Fortran Source or a Seasonic PSU.

As far as noise goes, the Coolmax is a little louder than my SilenX, but much quieter than my Fortron Source. If I were to compare it to another PSU, I’d venture to say it reminds me of my Seasonic, perhaps just a tad louder. I don’t have a sound meter that is sensitive enough to tell if it’s more or less quiet as my Seasonic 300, but to my ear it’s fairly close. For an inexpensive 450 watt PSU, I really like the Coolmax. Throughout the tests, it never produced enough noise to be heard over my Zalman CPU fan running at low speed. Even with all the case fans disconnected.

That's pretty impressive!!!

I'm using a Coolmax Taurus CX-350 in my system, and I find it to be very quiet too, at the Low and Automatic settings. On High, it moves a *LOT* of air, but it is a bit noisy, so I generally don't use it.

I'm not sure what kind of 120mm fan these things are using, but I'm not too worried--I've read somewhere that they are ball bearing fans, and to my ear, its definitely quiet enough.

I've been trying to see if I can talk Coolmax into sending one to SPCR for review, but so far, it doesn't seem like I've had any luck. I'd really like to see SPCR review it though, cause I agree, I think it is an excellent choice for those who want a quiet PSU on a budget. I paid only $29.99 for mine at AccuPC, and for the price, it seems like a VERY good unit--it looks to have fairly decent-sized heatsinks, it has Active PFC, and it has every imaginable kind of protection--short circuit, open circuit, overload, over-voltage, etc., and it has a good-looking fan grill, too. I'm therefore toying with the idea of sending one to SPCR myself if I can't get Coolmax (or one of its distributors) to send one to SPCR.

Great Idea! I just sent Coolmax an email with the same suggestion. I'd really like to see someone with the right equipment do a thourough review of this PSU as a potential candidate for Silent PCs.

The selection of low noise PSUs seems to increase gradually each year, but we really need more manufacturers who are willing to offer low noise PSUs at lower prices.

Hehe, thanks!! I've also been trying to contact some Canadian distributors, just in case they're willing to listen. Anyone else out there with some experience want to help in this campaign? I'm thinking maybe if enough of us chime in, they'll listen...

Like I say, count me as one person who thinks the Coolmax is a good option for those on a budget. If you want quieter still, I'm sure the fan can be swapped in this thing too, but I think even the stock fan is quiet enough for my purposes. I know the actual power supply circuitry probably isn't as efficient as a Seasonic, but then again, like I say, it is probably good enough for those who are on a budget, and don't necessarily want to pay over $100 for a Seasonic. I think it would be worth having SPCR review it just for this fact alone. I have yet to see ANYONE else, quiet enthusiast or not, do PSU reviews as thorough and as detailed as SPCR's.

HI

could u compare the coolmax a little better? can u hear the coolmax from a foot away? any strange noises? clicking, humming?

would u say for noise quietness
silentX>seasonic>coolmax>>Forton?

TIA
~RaNDoM

btw

the coolmax at newegg say it has NO PFC.

is newegg wrong?

TIA
~RaNDoM

I've had a hard time deciding on this one--Coolmax seems to indicate in all their literature that the unit is available with either Active or Passive PFC. In the manual that came with mine, it just says "active PFC." However, I still can't say for sure, because as I understand it, most (if not all) truly active PFC units that are made for both the North American AND European markets have full-range 100-240V input, but my Coolmax still has the traditional voltage input selector.

If I were to take a guess, I'd say the Coolmax is probably ONLY available with passive PFC in North America, and ONLY with 230V active PFC *WITHOUT* full-range AC input in Europe. A number of other PSU makers like Antec seem to do it that way, too. (Antec goes even further--I don't believe they have *ANY* kind of PFC on the units made for North America.) The only way I know of to find out for SURE would be to test the unit's power factor, but I don't have an easy way of doing that, since I lack the equipment.

Having said this, I'm still happy with mine--it works well, and its very quiet and reliable. Also, although the power factor may make a difference to the peak current draw of the unit, it won't increase your power bills in most residential areas here in North America. Also, be aware that the power factor makes NO difference whatsoever to the CONVERSION EFFICIENCY of the unit, which is what determines how much heat the PSU circuitry will generate--and we all know that the amount of heat generated is what ultimately determines how much cooling the unit will need.

That order sounds about right.

The only noise I can hear from the Coolmax is the sound of moving air from the fan through the grill. I've never heard it click or hum. My seasonic does make an anoying clicking sound, but is probably slightly quieter than the Coolmax overall. Both the Seasonic and the Coolmax are noticibly quieter than my Fortron. I can hear them both from one foot away, but have to strugle to hear them at about 3 feet. My Samsung Spinpoint seems to make more noise than the Coolmax, but that could be due to closer proximity (front of case vs. back of case) than anything else.

Mine does not have PFC. It does have a switch on the back for three fan speed settings. I think they were Low, Auto, and High. All my comparisons were done with the switch set on Auto. The fan does rev up a little under heavy load, such as extended gamming, but never gets anoying and is always very quiet during less demanding PC activities.

Since this is my first Coolmax, I don't have enough experience to rate its long-term reliability, but after using it for several weeks now I'm very happy with it so far. It's not as quiet as my SilenX, but it's been a much better fit for my overclocked (yet quiet) system.

Hey guyz

I went ahead and purchased the CoolMAxx tarus

I got the 400W version since it was only 10 bucks more.

Newegg and fedex really kicked ass this time, only took 2 days to get to my house. AWESOME service!!!

So far it is quiter then my old forton
I cant hear the fan at all

BUT

I can still hear a hum coming from it. i think i may have to try those silcia gaska things from vantac or antec.

What do u guyz think the hum could be?

I turned all off the fans to see if the hum was coming from anything else.

It was for sure not any of my fans.

Maybe my whole computer just hums?
What is the cause of humming?

Thx
~RaNDoM

What else is in your system? It could be drive vibrations.

How did you turn off the fan in the PSU? I can't turn off mine...

I am running a

barton 2500 OC to 3200(210x10.5)
Thermalright 947U with 92mm panaflo at 7V
Abit NfS-7 rev2.0
Antec 3700BQE case
2x 512mb Kingston HyperX PC3500
160gig SATA samsung spinpoint
1x 120mm evercool aluminum fan(soon to be a nexus)
9200np radeon
COOLMAX 400W Taurus CX Series


no front fan
I turned OFF ALL the fans and their was still a hum that i could hear from a meter away.

i'm not really sure what it is

~RaNDoM

ooooo

my bad

i meant all the fans expect the PSU

like including the heatsink fan

i have no diea how to turn off the PSU fan, open it and unplug it, but that would void the warrenty

~RaNDoM

IIRC, Samsung drives and BQEs don't mix well without suspension. Have you done this?

doesnt the rubber circle thing on the HDD slide dribe-racks prevent vibration?

could the HDD really make that much noise?

how would i supsend the drive if the HDD cage is like stuck in place?


~RaNDoM

hey thx sthayashi

i read that u had success using 1/4" Sorbothane strips

I am kind of an impaniet person. do they sell this stuff at home depot or lowes?

i live like 5 min away from a home depot.

btw, what exaclty did u order at McCathy?

4"x4"x1/4"? then chop it up into 4 pieces?

thx
~RaNDoM

Well, I think I had success. The problem is that the loud power supply seems to be overpowering any drive noise that I might have.

But yes, I ordered from McMaster-Carr online. I think it cost like $10 for a 4"x4"x1/4" sheet, but it was enough to do 4 hard drives. Also, for me, when I order, it always arrives the next day (I think there's a distribution center in Akron, OH, 2 hours away from me).[/url]

I actually chopped them up into 8 pieces. 2 for each of my hard drives.

btw sthayashi

how did the 1/4" size work? any better cooling then ralfs.

I went to my local home depot and they had no idea what i was talking about, i couldnt really say the word so i wrote it down on a piece of paper, i must of showed ten guyz and no one had any idea what i was looking for.

I guess i'm gonna have to order it, how much was shipping if u can remember.

~RaNDoM

Right--there is no way to turn off the PSU fan except by voiding the warranty. It probably isn't a very good idea in ANY case--I will absolutely 100% guarantee you that the PSU will burn to smitherines if you run it without the fan for any length of time.

That being said, I do hope the power supply is performing to your satisfaction. Like I say, it probably isn't the absolute best of the best, but in my opinion, I think it is extraordinarily good, considering the price. I guess it is what you could call a poor man's Seasonic Super Tornado. (Having never tried a Seasonic myself.)

hey Morpheusman or zuperdee

While i was testing my new nexuz 120mm fan, i was hearing a clicking. i was thinking it came from my new fan. but i turned off all my fans and i was listening and i could still hear a clicking?

I then realize it waS coming from the PSU fan. It is a small clicking but i can notice it from 1 foot away.
Does ur guyz coolmax PSU click?

Thx
~RaNDoM

Hey there, sorry for the delay. To answer your question: Yes, my Coolmax's fan clicks. How noticeable (or objectionable) is another matter. It seems to me it used to be more noticeable in my old computer case, but once I moved it into my new Antec SLK1600 case, I stopped noticing the clicking. I have a feeling it might become more noticeable as the fan revvs up. (My SLK1600 has much better ventilation than the old case, so it is possible my PSU is breathing more easily, and doesn't need to spin as fast as it did in the old case.) Main thing is, it doesn't bother me now.

For what its worth: a lot of fans out there click. See this thread for a discussion of the reason for it.

I also initially looked into replacing the fan in the Coolmax--the stock fan in the Coolmax appears to be a Top and Tech (T&T) fan, spinning at 2000 RPM, delivering 79.4 CFM at 35dB. (I found this out WITHOUT opening up the unit, because I do not want to void my warranty.)

If you really are set on replacing the fan, I'd recommend that you try to make sure you get a fan that matches the original specs as closely as possible.

Another thing you might want to try first though is decoupling your PSU with one of these.

Sorry for not answering you sooner. Truth be told, I can't tell about the cooling. All my drives are in Raid arrays and I haven't been able to get SMART information on them yet.

I CAN say that you have to be a little careful with the drive position. My 'Cuda V 120GB was too thick in combination with the Sorbothane to fit in the top bay of the BQE. Fortunately, the Samsung 40GB DOES fit.

The total cost for me on the Sorbothane from McMaster Carr was $9.20. You can determine the shipping costs from that.

I been linking ppl to this thread as a PSU reccomendtion and i wanted to answer some questions i been getting over and over.

The CoolMax i have does not hum, it was my HDD.

my coolmax fan does click, but from a foot or more away i cant hear it.

From a meter away i cant hear any fan noise or air whoosing or anything at all!

i have an antec 350 smart power, forton 350, and this coolmax 400 and for quietness i would say

CoolMax>>forton>>>>antec.

I also like the coolmax alot because it doesnt dent my wallet! and so far i have not have any problems with my computer at all and i use my computer for everything!


~RaNDoM