Is my power supply good enough?

S

seedler

n00b
Joined
Feb 3, 2010
Messages
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Currently running:

Biostar T5 XE
i5-750 @ 3.4ghz no voltage tweak on stock
Cosair XMS3 DDR3 1600
Evga 7900GS (from old setup)
Seagate Barracuda SATAII 750GB
Maxtor Diamondmax IDE 250GB
Enermax Noisetaker 485W PSU (18A dual 12V rails, 32A total)

Looking to get a Radeon 5850 this week.

The Enermax noisetaker is a quality PSU, but will it be enough to run both the i5-750 and the Radeon 5850?

If not, could someone recommend me a quality PSU that I can invest in for 5850 crossfire in the future?

Thanks in advance.
 
Not good enough for the HD 5850. That PSU is based on an older Enermax design and may not be fully capable of providing 32A on the +12V rail anymore. As such, I would not recommend it for your current system with a HD 5850 added on.

I recommend the Corsair 750TX 750W or Antec Truepower New TP-750 750W PSU if you plan on HD 5850 Crossfire in the future.
 
I second Danny's suggestion. It may have been a good PSU back in the day, but by today's standards it's old and it probably isn't up to powering a modern high-end rig.
 
seedler said:
What do you guys think of this one?

OCZ ModXStream Pro 600W, Dual 12V Rails 30A x 2
http://www.directcanada.com/products/?sku=13220AC8686&vpn=OCZ600MXSP&manufacture=OCZ TECHNOLOGY

Will it handle 5850 crossfire?
Click to expand...

Low quality and mediocre at best. Not capable of handling HD5850 Crossfire. Hell it wouldn't be good enough for one HD 5850. In addition, You need a QUALITY 750W PSU with a minimum of 60A on the +12V rail for HD 5850 Crossfire. That OCZ PSU only has 42A on the +12V rail.
 
No to OCZ. And 600W is low man, don't skimp on your PSU. In the long run you'll pay for being a cheap ass.

I recommend Corsair, too. Worth the extra $$.
 
Hm thanks, I'll remember to stay away from OCz.

Now I guess, the better question is, what is the most powerful card that I run with my current PSU?

5770? 5750? 5830 when it comes out in a few days?

I've seen people run 4890 and 4870 with i5-750 on worse PSUs, so that's why I thought I could get away with running the 5850 on my Enermax. I guess a less powerful card will have to do for now until the next upgrade.
 
5770 should be a safe bet. TDP is 108W -- 50W less than the HD 5850.

The performance of the 5770 is nice up to 1680*1050.


You have to remember it's not about just running the system. You need headroom for two things: upgrades, and time. How long do you think a 400W PSU is going to last running a 3.6GHz i5-750 and an OC'd HD 4890, for example?

For example, don't try to do something like my system (3.4GHz C2Q, 8GB DDR2, HD 5850 on a 300W). I'm not oblivious to the possibility of my PSU blowing something up or just causing general instability and crapping out within a matter of months (at which point I'll upgrade to the Shuttle PC63). You're smarter than that. ;)


Also, don't overdo the PSU either. If you get an 850W for a single 5850 you'll probably get coil whine, and the PSU's efficiency will drop since its relative load-to-peak will be so low.
 
As anyone on here will probably tell you, there's something to be said for spending a little extra cash on a good PSU.
 
Thanks for all the replies.

Got my 5850 and installed it, and also borrowed a watt meter from a floor mate.

Here are the results:

CPU - i5 - 750
20 x 200mhz = 4.0ghz, 1.368V, could probably go even higher with my 212 + cooler, temps at 54C under load right now.

GPU - HIS Radeon 5850
785/2321mhz core/mem.

Watt meter power consumption results:

Idle - 168W

Running Oblivion on highest settings - 291W

Running COD MW2 on highest settings - 305W

Running WOW on highest settings - 284W

Wish I could test with synthetic stress tests, but my backup drive died on me and I don't have software. But the results are pretty clear:

The 5850 is NOT power hungry at all. I could have gone with a 5870 and my 485W PSU would have handled that easily as well.

Although getting an excellent PSU is a wise investment, saving money on a good-enough PSU is a wiser one.
 
One key issue with your entire post: You're assuming that the Watt meter is remotely accurate. It's been shown time and time again that consumer level power meters are inaccurate with computer power supplies.

Some more info:
[Basic Power Supply Info]

Paul_Johnson said:
Yes and a quick search would turn up this topic a million times over. Here is the recap:

1) APFC can fool Kill-A-Watts into giving you abnormally low readings (some times giving better than 100% efficiency)

2) Power supplies derate with temperature anywhere from 2w/c above a nominal rated at value to 10w/c.

3) Kill-A-Watt's and most power meters sample too slowly to catch transient loads (the Transient load from our tests is 117w and is COMPLETELY missed by Kill-A-Watts).

4) Power supplies last longer if you stay in the 40% to 60% range of their output.

5) power supplies are quieter if you stay in the 40% to 60% range of their output.

6) Power supplies are cooler if you stay in the 40% to 60% range of their output.

The power meters in UPS software are just as bad. You have to spend some change before you get anywhere near an accurate power meter when your PSU has APFC.
Click to expand...
[Kill-A-Watt Inaccuracy]

Here's Paul Johnson's post about the inaccuracy of the Kill-A-Watt:
http://hardforum.com/showpost.php?p=1032190998&postcount=7

In addition, even if your numbers were remotely correct, refer back to items 4-6 of my above quote. Considering that a majority of PC hardware draws power from the +12V rail, that's 305W of power or so from the +12V rail. Your PSU only had 384W on the +12V rail. You're essentially loading the PSU to 80% of it's actual capability. With items 4-6 in mind and the fact that your PSU is old enough that more than likely 384W from the +12V rail might not possible, it still makes sense to upgrade your PSU.

So either way, that Enermax PSU was unsuitable for your PC.
 
Thanks, I'm happy with even stock performance as stock CPU/Video card settings runs everything on max as of now, so in this case I'll drop back stock speeds for both components and hopefully my PSU will last.

In a year or two when I decided to crossfire, I'll get a better PSU so in the mean time, hoping my Enermax won't die.

P.S.: If my PSU were to die on me in the future, is there a risk of damaging other components? Seems unlikely to me, but is this a considerable risk? (>5% of the time)?
 
seedler said:
P.S.: If my PSU were to die on me in the future, is there a risk of damaging other components? Seems unlikely to me, but is this a considerable risk? (>5% of the time)?
Click to expand...

Yes, a very real and substantial risk. The actual percentage points don't matter so you might as well consider it a 100% chance of the PSU taking something else out with it if you're prudent.


Once again, leave the 5850 at stock and undervolt it to 1.00v. It should be stable at that voltage, and you will save quite a bit of power. Performance loss will be negligible if you're at 1920*1200 and lower.
 
seedler said:
P.S.: If my PSU were to die on me in the future, is there a risk of damaging other components? Seems unlikely to me, but is this a considerable risk? (>5% of the time)?
Click to expand...

Yup there is a risk of the PSU killing your entire PC. Yes it is a considerable risk considering the age of the PSU and the 80% load you're putting on the PSU (assuming that those numbers were remotely accurate).
 
I'm unclear why his PSU is at risk with his current components.

485w PSU,

His max posted wattage is 305w (running COD) at the wall.

For argument sakes lets assume his metering output is correct and the efficiency is 80%.

305x80% = 244w
and his PSU is capable of 485w (600w at the outlet).

I'm not as knowledgeable as many members here but I'm confuse as to why his PSU is incapable/not recommended of powering this particular system?
 
kstud said:
I'm unclear why his PSU is at risk with his current components.

485w PSU,

His max posted wattage is 305w (running COD) at the wall.

For argument sakes lets assume his metering output is correct and the efficiency is 80%.

305x80% = 244w
and his PSU is capable of 485w (600w at the outlet).

I'm not as knowledgeable as many members here but I'm confuse as to why his PSU is incapable/not recommended of powering this particular system?
Click to expand...
It's an old PSU based on an old design, and it is most likely not able to reliably output its rated power any more.
 
kstud said:
I'm not as knowledgeable as many members here but I'm confuse as to why his PSU is incapable/not recommended of powering this particular system?
Click to expand...

Nor am I. Age and design aside, I think the PSU would work fine.

I don't understand the mindless buffing of power supplies myself. I forward the advice for those that genuinely are paranoid about a new system, but don't pay any mind to it myself. I have an older OC'd A64 X2 build with a 6800 Ultra that's been running on a no-name 300W PSU for 4.5 years now, so I really won't be convinced to buff up until I have to eat my words with a system. "You shouldn't put anything better than a 4850 on that [Shuttle 300W] PSU", they said...

But these are recommendations, and I guess it always helps to guide people towards a safer path than having them blow their system up and cry to you about it.

Many people who recommend PSUs also take into account [H]ard 24/7 use, like folding, or have experience in such activities. In these situations the PSU really does matter, and you never want to cut yourself short.

Also, a PSU blowing up on you and taking out your components can be one of the worst feelings in the world.
 
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^^^
Is your sig up to date? If my eyes aren't deceiving me...you're running a 5850 with a ~ 5year old 300w shuttle psu? LOL...nice....

The 5850 is really quite efficient when it comes to performance/power consumption ratio. It consumes less power than a 4870, 4890, etc....
 
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kstud said:
^^^
Is your sig up to date? If my eyes aren't deceiving me...you're running a 5850 with a ~ 5year old 300w shuttle psu? LOL...nice....

The 5850 is really quite efficient when it comes to performance/power consumption ratio. It consumes less power than a 4870, 4890, etc....
Click to expand...

The Shuttle PSU is less than a year old.. the other 5-year-old one is a nameless model with no APFC and some old ATX standard. It's still kicking and plays Oblivion without a hitch (though the 6800 Ultra's fan is just about to give out).

Yeah the 5850 is golden for its power efficiency. I appreciate it much more than I did the 5770 in that regard.. much more power for a couple more watts.
 
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