HD5850 and HD5870

viper200

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Apr 3, 2008
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Hi guys
would a Corsair VX550 Single 12V Rail (41A)
run either a HD5850 or a HD5870
and would it be worth upgrading from a 4890? to 1 of these?


 

cobot

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You will be fine and with plenty of power to spare, the chart he linked to is for the whole system at the AC source.
That means that the single 5870 system in the test uses 354W multiplied with the efficiency of the PSU used, probably around 80-85%.

354*0,85=300,9W

A 550W corsair? Pfff, it will run your computer while powering your blender, microwave and spaceship at the same time.
 

skolpo

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Yea, I know it was the whole system. I still think you should have a little bit of headroom for your PSU, since 354 is "almost" bare minimum when considering efficiency. He might also be running more power-demanding components than the test system, too.
 

cobot

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Headroom is good, yes, but remember that PSUs are rated after how much output they have, not how much the draw from the wall socket.
So very simplified, this PSU will be able to output 550W with an efficiency rating of 85%.
With other words, it will be able to transform 647W of AC into 85% (550w) DC and 15% of other energy, mostly heat.

As the power usage of the system in the test was measured at the AC source, it meas that the system really only needs around 80-85% of that from the PSU (depending on the efficiency rating) which will bring you to around 300W. That is only 55% of what that PSU can deliver.

I think that is enough headroom, especially since Corsair PSUs are known to be able to output even more than what they are rated for.

People ofter overestimate their PSU needs, but would be a shame if Viper went and spent money on a new PSU when it's not needed.




Yeah, I can't run crysis on ultra high while firing my phasers - just not enough power. :(

 

Jaysin

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If you can get good money out of your 4890 from less than knowledgeable folks then a 5850 may be worth it. The performance is better but it isn't a massive jump to where you should take a big loss to buy one. Moving up to the 5870 would be the preferred option.

The PSU is perfectly fine.