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Noob needs HD5870 power advice

Last response: in Graphics & Displays
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February 25, 2013 8:49:01 PM

Hello,

I'd like to know if I can install a HD 5870 (TDP 192W) in my pc without having to upgrade the 460W PSU. If I have to upgrade the PSU I won't buy the 5870, so I'm happy to approach safe wattage limits if needed.

My 460W PSU(link)



An online PSU calculator says I am currently using 290W with the system I have below:

Core2Duo E6550 2.33GHz
4GB DDR2 RAM
HIS Radeon HD 4850 (147 Watt) - (45W less than the 5870)
Everything else, 3 Hard Drives etc

Is it true that the 5870 requires 40 amps on the 12 volt rails? I've heard people say this is ridiculous as it would equate to a very high wattage, when it's rated at only 192W. Could someone clarify this point please?

Will my PSU support the HD 5870?
February 25, 2013 9:00:36 PM

it should handle it provided your current PSU has the connections needed for the card, I can't promise it'll work well though it would be safe to get a new PSU. you can get a good 600W fairly cheap.
February 25, 2013 9:55:43 PM

Can I get a second or third yay before I commit the $ on the 5870?
Related resources
February 25, 2013 10:17:08 PM

well according to the psu calc I used ( outer vision ) It recommends a 327W for your current setup, with a 5870, it recommends 381W. so that should be ok...

funny though. it recommends alot more for me but i have 2 5870's and an i7. so that has alot to do with it..

I would feel more comfy with a 650W QUALITY unit ( corsair and seasonic )
February 25, 2013 10:38:32 PM

Hard Line said:
well according to the psu calc I used ( outer vision ) It recommends a 327W for your current setup, with a 5870, it recommends 381W. so that should be ok...

funny though. it recommends alot more for me but i have 2 5870's and an i7. so that has alot to do with it..

I would feel more comfy with a 650W QUALITY unit ( corsair and seasonic )


Thanks but what I'm concerned about is the amps on the 12 volt rail issue - will my PSU handle the amps?
February 26, 2013 1:00:25 AM

192W/12v= 16A so you are at the limit for 1 rail however our cards can draw up to 352W each alone. proof: http://www.anandtech.com/bench/Product/511

This makes us revise the math. 352W/12v= 29.33A and you are dividing that by the slot and a 6 pin and an 8 pin. slot provides 75W 6 pin 75W and 8 pin 150W ( PCI express max W =300W iirc )
a b U Graphics card
February 26, 2013 1:15:07 AM

You'll do fine on that PSU 18 amps gives you 216 W and you got the other rail for the CPU
It dosen't seem like you're drawing any more power than the 4850


a c 114 U Graphics card
February 26, 2013 1:15:31 AM

Hard Line said:
192W/12v= 16A so you are at the limit for 1 rail however our cards can draw up to 352W each alone. proof: http://www.anandtech.com/bench/Product/511

This makes us revise the math. 352W/12v= 29.33A and you are dividing that by the slot and a 6 pin and an 8 pin. slot provides 75W 6 pin 75W and 8 pin 150W ( PCI express max W =300W iirc )


First that 352 is the FULL system NOT the card at all.

Proof


The 5870 is in this chart and that is CARD alone. EDIT... Stickmansam beat me to it. This just happens to be a review for another card with the 5870 listed.
http://www.techpowerup.com/reviews/MSI/GTX_650_Ti_Power...

Second, While 26(312watts) amps seems a bit low for a 5870 system I generally stay under that at the wall(2600K @ 4.4).

Your 65 watt cpu should help.

I HIGHLY recommend you get a power meter from the local hardware store. Many users would be surprised at actual computer power consumption.

Also for PCI-e slots. it is generally 75 watts for the slot 75 for a 6 pin and and 150 for an 8 pin(A 5870 only has 2 x 6 pin), while the newer pci-e slots are supposed to be rated at 150, very few are willing to pull that much power from it.
February 26, 2013 1:20:18 AM

I stand corrected Nukemaster. still I would want a more powerful PSU ( my rig pulls over 800W ) with bloomfield and 2 5870's

Edit: Both of my 5870's 1 XFX and 1 MSI lightning have 1 6 pin and 1 8 pin ( and 2GB not the 1GB )
a c 114 U Graphics card
February 26, 2013 1:23:16 AM

Damn what kind of clocks you got on that sucker.

I mean my old I7 920 at 3.5(rather low overclock) + 5870 never past 350 iirc. The worst thing about my 920 system was it rather high 150 watts or so at idle vs the 2600k with its sub 100(mid 70's with the new ssds).
February 26, 2013 1:35:36 AM

I have my i7 930 @ 4.5ghz ( posts at 4.6 but can't get it stable normally run at 4.4 ( 21x209 )though ) both 5870's are running 900 core and 1300 vram.
I have 12GB mushkin redlines 1600 6-8-6-24 running at 1676 stock timings. ( i have run it at 1900 8-9-8-24...
I am also running 14 fans and a swiftech 655 pump and lamptron touch fan controller 4 sammy F1 in raid 10 and 1 128GB crucial C300 and 1 512GB Crucial M4
a b U Graphics card
February 26, 2013 1:39:37 AM

nukemaster said:
Damn what kind of clocks you got on that sucker.


Probably just an inefficient power supply. For instance if each card is taking 175 watts and the rest of the computer 100 for a total of 450, then a 65% efficient power supply would suck 692 watts from the wall, where an 80% efficient one would pull 563 . . . So you can see where you can get up to 800 from the wall if you really try hard to be inefficient. Seems like a huge waste of power to me (unless of course you don't have a heater in the room). Possibly he's counting his monitor too or something?

My own machine is a 3570k w/ 7850, 2 spinning disks and an SSD, and if I run future mark, prime 95 and three drive benchmarks all at once the kill-a-watt hovers around 220watts from the wall. Playing games it's more like 160 - 180 watts.

edit: . . . or 12 fans too many, even if they are only 5 watts each that's still 60 extra watts . . . plus a couple of extra drives and 25 watts for a water pump . . .
February 26, 2013 1:44:19 AM

I am not counting the monitor you can check my specs above. and I used outer vision psu calc to determine PSU required. I have a corsair AX850 ( made by seasonic )
a b U Graphics card
February 26, 2013 1:45:01 AM

Hard Line said:
I am not counting the monitor you can check my specs above. and I used outer vision psu calc to determine PSU required. I have a corsair AX850 ( made by seasonic )


So you didn't actually measure it?at 90% efficient I still very much doubt you are coming anywhere near 800 watts from the wall.
February 26, 2013 1:50:47 AM

I do know my $400 monster cable measure 4 amps being drawn when gaming.. as a matter of fact my pc would routinely trip the circuit breaker when the AC was on ...to the point I built an extension cable out of high grade wall cable and routed it to the garage through the floor. my cpu oc's alone os 230-240W each gpu can pull up to 300W.. 300x2+240 then add 14 fans worth and 4 HD's the pump and the gpus are oc'd as well. I do plan to get a kill a watt.. but folding at home 24/7 for a week increased my elec bill $35 that month to give an indication and we pay 9.8c per kWh
a b U Graphics card
February 26, 2013 1:57:04 AM

4 amps @ 120v = 480 watts from the wall... at 90% efficient that's supplying 432 watts to your machine.

Just as a note I just googled the PSU recommending software that you mentioned and mine says the PSU wattage should be 359, but it actually measures from the wall at 220 absolute peak. So it seems like it over estimated by 62%. So if it said 800 for you, and that holds true then it would put it at 496 . . .

Seems that 480 from the wall isn't too far off.


February 26, 2013 2:00:44 AM

Are you adding in 14 fans, and tv tuner plus the pump as well? also the cpu overclock

Edit:
here is what it gave me:
Minimum PSU Wattage: 771 W
Recommended : 821W


according to this calc, my cpu draws 290W with the OC
a b U Graphics card
February 26, 2013 2:03:48 AM

Hard Line said:
Are you adding in 14 fans, and tv tuner plus the pump as well? also the cpu overclock


Your power bar is when it measured 480 watts (assuming 120v, but that's probably more like 110-115)

Also, FYI, a 15A breaker will generally trip when a 1500 watt AC unit and a 480Watt PC are turned on, as that's over 15A. You also generally don't want things like fridges and AC units on the same circuit as your PC.

February 26, 2013 2:08:41 AM

Yeah I am aware of that. the AC runs 9.8A iirc ( i could be off .. ) it is an energy saver as is everythign else in the house. all ccfl bulbs and everything is energy star rated ( even switching out the boiler and water heater to high efficiency ( bill are crazy high)

I hope you understand i am not trying to argue just discuss... the strip read 4A with only 1 gpu ( before adding the second 1 ) I have since moved pc from strip so i can't measure.
a b U Graphics card
February 26, 2013 2:11:02 AM

Hard Line said:
Are you adding in 14 fans, and tv tuner plus the pump as well? also the cpu overclock

Edit:
here is what it gave me:
Minimum PSU Wattage: 771 W
Recommended : 821W


according to this calc, my cpu draws 290W with the OC


According to the over estimation by 62% you mean? I would have a hard time believing that the CPU alone would be able to eat up the 180 watts even after you remove the 62% of phantom energy they are over estimating by.

If it's really eating that much why not upgrade to an i7-3770k and save the money in power in a few months?
February 26, 2013 2:15:01 AM

actually I planned to go with haswell and 8xxx or 7xx when they come out. my rig still performs on par with current high end so performance wise i can't see the upgrade but power savings should be significant

Edit: according to the "over estimating page" I will go from 821W recommended and 771 minimum to 581W recommended and 531 minimum just changing cpu and gpus ( 930 to 3770 ( oc that as well to 4.8 ) and from 2*5870's to 7970
a c 114 U Graphics card
February 26, 2013 2:15:47 AM

4.5 for that cpu is INSANE.

I can see some power use from that for sure.

I think we have come off topic here.

I think the OP should pull it off, but I would recommend looking for a new power supply in the future just for that extra bit of safety.

To add to this. My i5 750(undervolted) + 650 ti(and a notebook drive + SSD) games under 150 watts most of the time :) 
a b U Graphics card
February 26, 2013 9:39:32 AM

nukemaster said:
I think the OP should pull it off, but I would recommend looking for a new power supply in the future just for that extra bit of safety.


I think a better idea for the OP is if they are that concerned about power usage that they switch up to a 6870 instead. It's arguably faster in some cases (but essentially the same), but according to anandtech's benchmark it uses far less power under load. http://www.anandtech.com/bench/Product/294?vs=290&i=228...

Even better would be a 7850, which is much faster and uses even less power, and is also good enough to keep around for another year or two if they went to an i3/i5 sandy bridge. http://www.anandtech.com/bench/Product/511?vs=549&i=413... . . . You can find refurbs or ebay auctions pretty darn cheap in most cases if cost is a huge issue.





February 26, 2013 10:19:05 AM

Thanks everyone for your input. I don't mind the thread going off topic, it's important to get to the truth of things and it just means a few OT posts were added to a not too-important thread.
February 26, 2013 1:11:25 PM

I would just like to add that I found this on guru 3d's review of the 5870. ( this is total system power ( which is what I would use to choose a psu not just the gpu )

Recommended Power Supply

So here's my power supply recommendation:

Radeon HD 5870

The card requires you to have a 500 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 40 Amps available on the +12 volts rails.

Radeon HD 5870 CrossfireX

A second card requires you to add another 188 Watts. You need a 700+ Watt power supply unit if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 55~60 Amps available on the +12 volts rails.

For each card that you add, add another 200 Watts as a safety margin.

There are many good PSUs out there, please do have a look at our many PSU reviews as we have loads of recommended PSUs for you to check out in there. What would happen if your PSU can't cope with the load?:

bad 3D performance
crashing games
spontaneous reset or imminent shutdown of the PC
freezing during gameplay
PSU overload can cause it to break down
a b U Graphics card
February 26, 2013 5:35:30 PM

Hard Line said:
The card requires you to have a 500 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 40 Amps available on the +12 volts rails.

Radeon HD 5870 CrossfireX


My own graphics card says you need to have a 500 Watt power supply for single cards, and a 600watt for crossfire. Yet here is my machine sucking a grand total of 220 watts from the wall. Even if you assume the only thing using power in my machine is the graphics card and crossfires it it would be pulling 440 watts from the wall, on my 82% efficient power supply that would still only be delivering 360 watts . . . something that most good quality 450 - 500 watt power supplies can do without breaking a sweat.

Anyway, we get it, the era of incredibly inefficient heater style cards is over, and over the next two generations of both CPU's and GPU's things are much much better now. Hence the 220 watts in my machine that does only slightly less performance to 650+ watts that you're sporting.

That's why I just gave up and recommended the OP not bother buying a PSU and 5870, but sink the extra cash in to a 6870, or even 7850 if possible, since both offer similar or better performance for much less power.
February 26, 2013 7:27:52 PM

Traciatim said:
My own graphics card says you need to have a 500 Watt power supply for single cards, and a 600watt for crossfire. Yet here is my machine sucking a grand total of 220 watts from the wall. Even if you assume the only thing using power in my machine is the graphics card and crossfires it it would be pulling 440 watts from the wall, on my 82% efficient power supply that would still only be delivering 360 watts . . . something that most good quality 450 - 500 watt power supplies can do without breaking a sweat.

Anyway, we get it, the era of incredibly inefficient heater style cards is over, and over the next two generations of both CPU's and GPU's things are much much better now. Hence the 220 watts in my machine that does only slightly less performance to 650+ watts that you're sporting.

That's why I just gave up and recommended the OP not bother buying a PSU and 5870, but sink the extra cash in to a 6870, or even 7850 if possible, since both offer similar or better performance for much less power.



I do agree with your recommendation of getting a new card if possible. I may have performance close to top end current hardware, but I am paying for it in the electric bill.
!