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Is a Corsair tx650w sufficient for hd4870 crossfire?

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June 29, 2008 4:34:34 PM

the rest of the set up would look like this:
Antec Performance One P182
Gigabyte GA-X48-DS4
Corsair TWIN2X DDR2 4096MB (2x2048MB)
Intel Core 2 Duo E8400
Saphire Radeon HD 4870
Samsung SH-S203D
Samsung Syncmaster 226BW
Seagate Barracuda 7200.11 500 GB
Thermaltake Blue Orb II
June 29, 2008 4:41:02 PM

Official minimum power requirement for cf 4870 is 500w. It should be enough, but it's cutting a bit close. If you already have the computer, try it out, should work. If you're still haven't ordered parts, get a larger psu.
a b ) Power supply
June 29, 2008 4:47:56 PM

^ yes it has the watts and the amps to run them both, but if you're buying new then spend the extra $10 to get a 750w

Minimum System Requirements for a Visiontek HD4870

PCI Express® based PC is required with one X16 lane graphics slot available on the motherboard

500 Watt or greater power supply with two 75W 6-pin PCI Express® power connectors recommended (600 Watt and four 6-pin connectors for ATI CrossFireX™ technology in dual mode)

Certified power supplies are recommended. Refer to http://ati.amd.com/certifiedPSUfor a list of Certified products

1GB of system memory

Installation software requires CD-ROM drive

DVD playback requires DVD drive

Blu-ray™ / HD DVD playback requires Blu-ray / HD DVD drive

For a complete ATI CrossFireX™ system, a second ATI Radeon™ HD 4870 graphics card, an ATI CrossFireX Ready motherboard and one ATI CrossFireX Bridge Interconnect cable per board (included) are required
Related resources
June 29, 2008 4:58:04 PM

Power wise the TX650 is fine but it doesn't have enough PEG connectors. Molex -> PEG adapters should do the trick, but the TX750 isn't much more expensive and it has 4 PEG connectors to boot.
June 29, 2008 4:58:40 PM

dagger said:
Official minimum power requirement for cf 4870 is 500w. It should be enough, but it's cutting a bit close. If you already have the computer, try it out, should work. If you're still haven't ordered parts, get a larger psu.


Hello,

I am sorry for hijacking the thread.

I would like to have 4870 . i have corsair 550 W with 41 amp on single rail. my current setup is Q6600 at 3.3, 4gb ram, 1 hd, 2 optical drives.

Can my psu handle a single 4870?

Thanks.
June 29, 2008 5:16:28 PM

htoonthura said:
Hello,

I am sorry for hijacking the thread.

I would like to have 4870 . i have corsair 550 W with 41 amp on single rail. my current setup is Q6600 at 3.3, 4gb ram, 1 hd, 2 optical drives.

Can my psu handle a single 4870?

Thanks.

It should work. But cuts a bit close. When oced, q6600 eats up a huge amount of power.
June 29, 2008 6:21:31 PM

the samsung 2253lw is a very impressive lcd panel imo, you may want to take a look at that one as well. Furthermore it's carried at local stores like costco, so you could just pick it up rather than having to ship it back if it has a bad pixel or two (i own one and havn't had a bad/stuck pixel thus far).

I also think that the psu you selected might be a viable option, but seeing as how the output power of a psu degrades slowly, You may want to go with a previous suggestion and gett the extra 100 watt overhead for longevity more than anything else.
June 29, 2008 6:27:36 PM

ok, so 750W it is then. how about brand name then? corsair is a good psu, no? quiet?
a c 139 ) Power supply
June 29, 2008 6:35:32 PM

htoonthura said:
Can my psu handle a single 4870?

With the 4870 and your OC'd Q6600 you'll still be under 400Watts total consumption. This chart is from XBitlabs and they used a 8800GTX as a video card.

And we know that the 4870 uses almost identical power as 8800GTX. http://techreport.com/articles.x/14990/15
Your Corsair 550VX will handle the 4870 easily.
June 29, 2008 6:58:12 PM

No psu work at 100% efficiency, even the best ones is about 80% efficient. Plus not all of a psu's wattage is routed to 12v rails, which support cpu, gpu, hdds... basically every major power hungry component. The wattage available to cpu/gpu/hdd is only a fraction of total wattage listed on specs. Also, psus degrade over time, so you need headroom as buffer. And lastly, it's always a good idea to have extra room for possible future upgrade or just to be on the safe side.
June 29, 2008 7:05:39 PM

Where are they measuring the wattage, at the socket? If so, then the real load is the wattage times the efficiency at that wattage with that PSU.

So if it's measured at the wall it's even a lower actual load.
a c 139 ) Power supply
June 29, 2008 7:12:08 PM

Zorg said:
So if it's measured at the wall it's even a lower actual load.
Correct.
June 29, 2008 7:14:43 PM

So, is it at the wall? you didn't link the article that you got the original graph from.
June 29, 2008 7:21:56 PM

htoonthura said:
Hello,

I am sorry for hijacking the thread.

I would like to have 4870 . i have corsair 550 W with 41 amp on single rail. my current setup is Q6600 at 3.3, 4gb ram, 1 hd, 2 optical drives.

Can my psu handle a single 4870?

Thanks.

The VX550 will handle that. It is highly efficient even up to its maximum rated output.
http://www.jonnyguru.com/modules.php?name=NDReviews&op=...
kel varnsen said:
ok, so 750W it is then. how about brand name then? corsair is a good psu, no? quiet?

The TX750 will serve you very well.
http://www.hardwarecanucks.com/forum/hardware-canucks-r...
http://enthusiast.hardocp.com/article.html?art=MTQwMyw0...
http://www.jonnyguru.com/modules.php?name=NDReviews&op=...

And I have no affiliation whatsoever with Corsair, I just think they make some kickass power supplies :sol: 
June 29, 2008 7:29:57 PM

Come clean, we know you work for them. :lol: 
June 29, 2008 8:14:51 PM

Thank you guys.
July 4, 2008 11:08:59 PM

dagger said:
No psu work at 100% efficiency, even the best ones is about 80% efficient. Plus not all of a psu's wattage is routed to 12v rails, which support cpu, gpu, hdds... basically every major power hungry component. The wattage available to cpu/gpu/hdd is only a fraction of total wattage listed on specs.


Just not true... the rated wattage is it's OUTPUT. If a supply is 80% efficient at it's rated wattage of 550w, then it will pull 687.5w from the wall to do it. Also almost every modern PSU can supply 90%+ of it's total power to it's 12v rails. Go spend a month on jonnyguru.com forum and come back when you know something.

When they say 500w minimum that's even being paranoid. you will be just FINE with even a 550w. Bottom line. But a 650w+ Antec or Corsair would never hurt. ;-)
July 6, 2008 12:03:54 AM

dagger said:
No psu work at 100% efficiency, even the best ones is about 80% efficient. Plus not all of a psu's wattage is routed to 12v rails, which support cpu, gpu, hdds... basically every major power hungry component. The wattage available to cpu/gpu/hdd is only a fraction of total wattage listed on specs. Also, psus degrade over time, so you need headroom as buffer. And lastly, it's always a good idea to have extra room for possible future upgrade or just to be on the safe side.


correct, but xx% efficiency means that your power supply will need to draw that much more out of the wall. For instance, if the power supply is rated 80% efficiency at a 400 watt load, where the maximum output is 550-watts (at 50c or whatever), that means that for the power supply to output 400-watts, it would need to draw 500-watts out of the wall.

I've posted this before, in the Tom's Hardware low budget test, SLI 8800GT's + E7200 + a NF 750N chipset (which uses up a lot of power) was completely fine, stable and cool under a 400-watt unit. A 4870 CF or a 4870 should be perfectly fine under even a quality 550-watt PSU
a c 139 ) Power supply
July 6, 2008 1:35:15 AM

Zorg said:
So, is it at the wall? you didn't link the article that you got the original graph from.

That graph was out of the Q9300 review @ http://www.xbitlabs.com/articles/cpu/display/core2quad-...
That article did not specify how they measure the actual power usage but they have covered their testing methodology in several forum discussions.
And at other websites that do specify how they measure (at the wall socket) the power draws in that Xbit chart are wholly consistent.
A good example would be the TechReport site: http://techreport.com/articles.x/14573/15
"Our Extech 380803 power meter has the ability to log data, so we can capture power use over a span of time. The meter reads power use at the wall socket, so it incorporates power use from the entire system—the CPU, motherboard, memory, graphics solution, hard drives, and anything else plugged into the power supply unit. (We plugged the computer monitor into a separate outlet, though.) We measured how each of our test systems used power across a set time period, during which time we ran Cinebench's multithreaded rendering test."
a c 144 ) Power supply
July 9, 2008 6:23:58 AM

htoonthura said:
Hello,

I am sorry for hijacking the thread.

I would like to have 4870 . i have corsair 550 W with 41 amp on single rail. my current setup is Q6600 at 3.3, 4gb ram, 1 hd, 2 optical drives.

Can my psu handle a single 4870?

Thanks.


Based on actual measurements, my Q6600 OC'ed to 3.6 GHz in an EP35-DS3P pulls 9.5 amps - about 120 watts. Corsairs are pretty conservatively rated PSU's. If you have a VX model, it's really a 650 watt PSU with a 550 watt sticker on the side. You'll be fine.

danbfree wrote:
"Just not true... the rated wattage is it's OUTPUT. If a supply is 80% efficient at it's rated wattage of 550w, then it will pull 687.5w from the wall to do it. "

True, thereby answering a very common misconception about efficiency. I usually use 400 and 500 watts to illustrate this(I'm old, simpler numbers).

and:
"Also almost every modern PSU can supply 90%+ of it's total power to it's 12v rails. "

My Antec 650 watt TP3 box says "three 19 amp 12 volt rails, max output 52 amps (624 watts)." Possible, but not likely.

!