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HD 3850 on 420w PSU

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February 17, 2013 6:50:35 PM

Hello everyone. I just bought Sapphire Radeon HD 3850 512MB AGP for my agp rig for 30Eur, my question is: will my PSU be able to support it? :


:o  On Sapphire website it says that I'll need 450W with al least 30A on 12V rail :(  But I also found this:


So the whole system used 200W:

Intel Core 2 Duo E6850 (3GHz)
Asus P5E-N SLI (NVIDIA 650i chipset)
4GB Crucial Ballistix DDR2-1067 memory
PC Power and Cooling 750W PSU
Windows Vista Ultimate (32-bit)

Considering I have AGP rig (P4 Northwood @2.4Ghz/ CompaqD510 i845G / 2GB (2x1GB) DDR400) I hope I shouldn't go above 200W full load, and this PSU has 216W output on 12V rail... I'm confused... So can I at least try with this PSU or buy something else? Thanks in advance.

More about : 3850 420w psu

a b ) Power supply
February 17, 2013 9:08:41 PM

That PSU exceeds the requirements of that video card. Total system power could be slightly over 200W. 12V requirements obviously are much lower than that.
a c 151 ) Power supply
February 18, 2013 1:58:03 AM

The HD 3850 demands 75W at max. Depending on which version of the AGP slot your PC uses, the card may too much for the slot alone to provide. Some AGP versions supply as low as 25W to the slot. Other AGP variations can supply up to 110W to the slot. However, if your HD 3850 has a 6-pin header on it for external power, you should be OK with the external cable supplying it power. If the 420W PSU can't keep up, you will know it by the fact that it will cause a re-boot or shut down due to low voltage.
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February 18, 2013 2:20:45 AM

clutchc said:
The HD 3850 demands 75W at max. Depending on which version of the AGP slot your PC uses, the card may too much for the slot alone to provide. Some AGP versions supply as low as 25W to the slot. Other AGP variations can supply up to 110W to the slot. However, if your HD 3850 has a 6-pin header on it for external power, you should be OK with the external cable supplying it power. If the 420W PSU can't keep up, you will know it by the fact that it will cause a re-boot or shut down due to low voltage.


Slight correction there, most AGP cards use molex connectors for extra power not the 6 pin PCIE connector.
a c 151 ) Power supply
February 18, 2013 2:32:21 AM

whooleo said:
Slight correction there, most AGP cards use molex connectors for extra power not the 6 pin PCIE connector.

You may be correct to some extent. But all the HD 38XX cards I've ever seen have had the conventional PCIe 6-pin header. And one like the OP refers to: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
...has a 6-pin header.
a b ) Power supply
February 18, 2013 2:33:31 AM

that should be fine.

February 18, 2013 1:02:03 PM

clutchc said:
You may be correct to some extent. But all the HD 38XX cards I've ever seen have had the conventional PCIe 6-pin header. And one like the OP refers to: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
...has a 6-pin header.


hmm. Interesting well you learn something new everyday!
a c 151 ) Power supply
February 18, 2013 6:15:35 PM

whooleo said:
hmm. Interesting well you learn something new everyday!

That's why I like it here. I never quit learning. :) 
February 18, 2013 7:19:14 PM

Thanks everyone!



looks like 8pin (4x2), guess I should get this?

a c 151 ) Power supply
February 18, 2013 7:53:20 PM

8-pin! Didn't think they used that big of a connector on the 75W HD 3850. But yes, that looks like the correct adapter to go from a PSU Molex to the card's 8 pin PCIe if your PSU has no PCie connector available. Is that a pic of your actual card?
February 18, 2013 8:03:48 PM

clutchc said:
8-pin! Didn't think they used that big of a connector on the 75W HD 3850. But yes, that looks like the correct adapter to go from a PSU Molex to the card's 8 pin PCIe if your PSU has no PCie connector available. Is that a pic of your actual card?

Yes, according to online auction where I bought it, should get it in couple of days...
a b ) Power supply
February 19, 2013 12:24:38 AM

even when u think u know it all u learn something new

!