Which PSU?

By Decka17 ยท 29 replies
May 17, 2008
  1. Hi all,

    I've been debating on which PSU to purchase, to replace my 400W I have atm. I can't run any games with my 8800GT and I believe its the PSU's fault, so I might as well get rid of the old thing and buy a new one.

    I've had my eye on a few PSU's, but I've heard a lot about the 12v rail needing at least 24 amps on it. All the PSU's I've looked at have several 12v rails with <21 amps on each, would this do? I've heard it doesn't matter how many 12v rails you have, its how many amps are on the single rail that counts...

    I've been looking at the Cooler Master Real Power 550W, which has three 12v rails with 18A, 20A and 10A on them at peak.

    My system is:
    Intel Pentium 4 3Ghz (soon to be Core 2 Duo 2.4Ghz)
    Windows XP Home
    Kingston DDR2 1GB
    Asus EN8800GT
    Gigabyte P31-DS3L
    400W PSU
  2. SNGX1275

    SNGX1275 TS Forces Special Posts: 10,742   +422

    I can't 100% confirm this, but I think those 'requirements' are based on total provided by the PSU, as if it only had 1 12V rail. Now this gets interesting when there are multiple rails because there seems to be a bit of inconsistency on what the PSU TOTAL amperage for 12V is, and really 'total' isn't that important because nothing itself is going to pull anywhere close to total. So we kind of go full circle since the video card itself is going to pull more than any other component.

    What I can tell you for sure is that that GT uses less power than my 8800GTS 320, and I run that on a Noisetaker II 485W, it has 22A on each 12V rail.

    PC Power&Cooling had it right all along sticking with a single rail. Dual and Triple rails were a fun marketing thing that worked, and in reality all it was doing was providing a cheapass way out of making a PSU that could deliver massive power at one voltage. Its easier/cheaper to make several 12V lines that are relatively weak than it is to make one line that has huge power potential. I think we will see many more manufacturers jumping back to single 12V rail systems for their high end models.

    So I guess in short, that Cooler Master will probably work. Consider that 20 amps on a 12V line means 240 watts, and there is NO WAY that card can pull anywhere near that much power, probably half of that.

    I would seriously consider the Enermax Noisetaker II that I linked rather than that Cooler Master one. Personally I think Enermax PSUs are of superior quality, the Enermax is cheaper (same price on newegg if you count the $10 rebate from Cooler Master). I've established that my system runs fine with a higher power draw card.

    Get what you want though, that CM will probably work fine. Just personally I'd take a lower wattage enermax over a cooler master.

    Let me get 1 more edit in here while I'm doing these things :)
    There seems to be a trend, well I guess it isn't even a trend since I've been seeing this for a long time.. But people that don't know how DC power works end up giving advice on PSUs and its a 'bigger is better' mentality. Now in this poster's case a 550W wasn't outrageous, its still way more than will ever be used by that system, but at least he didn't name a 650+ PSU. It is becoming mine, as well as a few others on this board's personal crusade against misinformation on power consumption. Modern systems simply do not need 600W or higher power supplies. Rare exceptions are in SLI/Crossfire configurations of extremely high end video cards paired with very high end overclocked processors and probably watercooling as well.

    Really what it amounts to is that if you have to ask what wattage PSU you need you likely don't need anything higher than 500. Because if you were putting together a system that required more than that you'd likely know enough about your components to know what PSU you needed.
  3. Decka17

    Decka17 TS Rookie Topic Starter Posts: 21

    Hmmm unfortunately, the store I usually (and only) buy from doesn't supply any enermax PSU's.

    So you're sure the Cooler Master will suffice, and won't crap out after a year or two powering the 8800 on modern games? Thats the reason I'm looking at a 550W PSU, to future-proof myself, at least PSU wise. Plus, the 550W edition is only $3 more expensive than the 500W edition, so why not :p
  4. SNGX1275

    SNGX1275 TS Forces Special Posts: 10,742   +422

    Well if you are stuck to a supplier.. Provided you don't get a defective one from the start it should work fine, Cooler Master make decent PSUs I think (but better cases).

    If your only concern is that I didn't explicitly say your 20 is going to be good for a card that 'requires' 24 then let me assure you, that will be fine.

    My point about the enermax vs cooler master is I personally believe enermax to be of higher quality. But cooler master still isn't what I would consider 'bad'. The quality does matter though, because if you get some off brand really cheap 800W psu, it is almost certainly of terrible quality and will fail if you approach even 60% of its load (I just made that 60% up, but point is you can't push cheap PSUs and expect them to deliver).
  5. Decka17

    Decka17 TS Rookie Topic Starter Posts: 21

    Hehe yeah, I wasn't planning on buying any generic brands, and I assumed Cooler Master would make a good PSU. I don't know what the 8800GT would need, amps wise, the 24 was only what I heard from other people.

    Thanks for your advice, looks like the Cooler Master it is!
  6. SNGX1275

    SNGX1275 TS Forces Special Posts: 10,742   +422

    You'll be fine I'm sure, to follow ohms law 24A on 12V will = 288Watts. That simply won't happen with that video card, it won't even come close to drawing that. So my thought is (like I said in the first reply) that those requirements are made based on if you only had 1 12V rail, compensating for what the rest of your components would draw.
  7. Decka17

    Decka17 TS Rookie Topic Starter Posts: 21

    Oh okay I understand now, so 24 amps on a single 12v rail for the video card PLUS everything else to run fine on it.

    I should be good then :D
  8. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

    Just out of curiosity, what was the problem with your old PSU? Did it cause BSODs with games?
  9. Decka17

    Decka17 TS Rookie Topic Starter Posts: 21

    I'd love to tell you, but not quite sure what BSOD means, not good with terminology :p

    In any case, since I installed the 8800, it wouldn't be able to play any graphics intensive 3D games. It would get about 5 seconds into loading the application, then reboot.

    All explained here:

    (since then I've assumed the PSU is the problem, but still open to suggestions)
  10. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

    Have you tried measures to cool the card down. Pointing a desk fan into the case is a great idea IMO.
    Also, what are the specs on that 400W PSU?
  11. Decka17

    Decka17 TS Rookie Topic Starter Posts: 21

    It's idle temp is at 49C, according to SmartDoctor :S I'm guessing thats bad, I might do that.

    And no idea, it came with the case. I guess its generic.

    EDIT: If it was overheating, wouldn't that happen a few mins into the game at least? Like, Windows is crashing only a few secs after I start up the game, so I assumed not.
    The card is also the ASUS 8800GT with the newer, bigger cooler and fan.
  12. SittingDuckie

    SittingDuckie TS Rookie Posts: 47

    I get the impression that replacing your power supply is a bit of a shot-in-the-dark attempt at fixing this? I'd be really interested to know why you think the psu is causing you to blue-screen. There is probably a number of things you should try before dishing out the cash for a new psu, but before we pile on suggestions just wanted to check if you are sure its the psu?
  13. Decka17

    Decka17 TS Rookie Topic Starter Posts: 21

    Nope, not sure its the PSU. It's just been suggested by a few other people that it IS the PSU, and it doesn't seem too unlikely. And I'm more than welcome to suggestions, feel free to give me any that are applicable :p
  14. SittingDuckie

    SittingDuckie TS Rookie Posts: 47

    Then please to be trying things that don't cost you anything first. You really don't want to buy a new PSU and then find the same thing happens. I'm not the pro some of these guys are, so hopefully they'll give you some tips on solving the issue, but in the meantime, here's a few recommendations:

    Have you downloaded the latest drivers?

    Try putting your old graphics card back in....does it still work? If not, you have other problems

    Once tried, can give re-seating your new gpu a go. Everything plugged in? Just asking as I had a similar set up to yours previously, but the generic connectors on the psu couldn't support the latest nvidia graphics cards, but I doubt your system would start if that was the case.

    Do you have a mate with a pci express slot that could be used to test your gpu on? Try to rule that out as the problem.

    Then if the gpu works fine and the old setup works fine and the drivers are up to date, might be looking at psu or other compatibility issues, but see what you find.
  15. Decka17

    Decka17 TS Rookie Topic Starter Posts: 21

    Drivers are up to date, and I've been using onboard graphics on my old motherboard 'till now lol. I thought it was about time to get a new PSU anyway, since the one I have atm is 3 years old, and if that eliminates the problem then so be it :D

    Everything is plugged into the GPU... Does it matter which connectors from the PSU I use for the two power connectors for the GPU? If that isn't any problem then I doubt its that issue...
  16. SittingDuckie

    SittingDuckie TS Rookie Posts: 47

    Er not sure tbh, suppose it could. my 9800gx2 glows green at the power plugs if they are in correctly, orange otherwise. not sure about the 8800s, might use the same thing, guess if u can see any orange lights down there you might wanna be worried, but as I said, doubt that it would display at all if that was the case.

    Does the game start using onboard graphics?

    Can you at least borrow a friend's PSU and test for the same problem with that?

    I had a problem with the graphics card on my 4yr old PC. fan stopped on the heatsink, then i broke the damn thing trying to replace it. Cut a long story short, I ended up replacing the whole thing. Anyway, might want to think about whether you would be upgrading ur whole PC sometime soon anyway, could either do that in conjunction with ur new psu and gpu, or just get a psu thats a bit future proof, i.e. modular and around 500w. Just something to think about.
  17. Decka17

    Decka17 TS Rookie Topic Starter Posts: 21

    Ummm...no green/orange light.

    And this new motherboard has no onboard graphics. I've been using a different motherboard 'till now, then I got a new mobo/8800 at the same time.

    No I don't...think any of my friends have a spare PSU they could lend me. I think... anyway, I'm looking for a solution sometime in the near future, so a new PSU is fairly short term :p
  18. SittingDuckie

    SittingDuckie TS Rookie Posts: 47

    okay, hope it works for you, I just personally wouldn't recommend replacing hardware without attempting to isolate the problem. Good luck.
  19. mke

    mke TS Rookie Posts: 90

    dunno if this helps you out on your calculations, but quite recently my newly build systems psu got fried. It was a new 650W Orryx psu that i purchased for 36GBP, i used it to run a Gigabyte N680-SLI DQ6 with a E6320 core2duo, 2XMS DDR2 gig ram, a 8800GTS and 5 sata disks. the psu got friend the minute i pluged it in and switched the power cycle on. All connections where fine, so I am 99.999999999% certain it was due to the cheap psu.
    Now i got a Thermaltake 750 Toughpower psu for 89BGP and everything works as it should.
    When u get a psu, check it can handle what you need, and most importantly, that it is of good quality, e.g. above tier 2 i would say..
    gluck with your quest
  20. captaincranky

    captaincranky TechSpot Addict Posts: 13,029   +2,558

    Coolermaster >>> Sucks

    Coolermaster has the worst rebate and customer service I've ever encountered.
    Buy it at your own risk.

    As always, your results may vary.
  21. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

    That might be so, but their Real Power Pro PSUs are right up there with others like Antec and Corsair. JonnyGURU consistently rates the PSUs from this range as being among the best.
  22. Decka17

    Decka17 TS Rookie Topic Starter Posts: 21

    Regrettably, I'm stuck to the one supplier (MSY), and they only stock SHAW, Thermaltake, Gigabyte, Coolermaster, Super Flower (???), Topower, Antec, Huntec, Seasonic.

    So does anyone have any good suggestions for the above brands, around the below $100AU mark like the CM I suggested?
  23. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

    Antec and Seasonic are the best brands out of those. See if you can find the Antec Earthwatts EA500. It provides 34A on the +12V rails combined, which is more than enough for your specs.
  24. captaincranky

    captaincranky TechSpot Addict Posts: 13,029   +2,558

    Terrorism: at Home and Abroad.......!

    Who did the artwork for MSY's website, Osama Bin Laden?

    Antec's customer service is great! The EA-500 looks good to me too.

    Antec replaced a failed "Smartpower 350)" with a brand new Earthywatts EA-380, no questions asked.

    Coolermaster still hasn't sent me a fifty cent plastic foot for a case I purchased in January 2008, in spite of 3 phone calls to customer service. To a named CS representative at that!
    Nor have they bothered to cut a rebate check for the same case which I mailed Feb 6, 2008. I have proof of mailing on that.
    Newegg is currently working on that for me.

    So, unless "JonnyGURU" is planning to take up the slack for Coolermaster's support, I'd go with the Antec.

    The usual disclaimer: That only matters if you need customer support. You could go through live blissfully ignorant of any of this, assuming nothing goes wrong. Hey, and it might not, right?
  25. Decka17

    Decka17 TS Rookie Topic Starter Posts: 21

    Heh yeah the MSY website...and store...aren't particularly flashy. But hey, who cares really :p

    And I'm not too concerned with customer service... Either way its a tossup between CM 550W Extreme and Antec EA 500W. Though leaning towards the CM still. Anything better about the Anetc compared to it? Just better reliability?
Topic Status:
Not open for further replies.

Similar Topics

Add your comment to this article

You need to be a member to leave a comment. Join thousands of tech enthusiasts and participate.
TechSpot Account You may also...