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Ati 4850 on a 400W power-supply?

Last response: in Graphics & Displays
April 20, 2009 7:15:49 PM


I have a question; I want to upgrade my Graphics-card to a Ati 4850.
But I don't know if my power supply is strong enough for it.

It's a nameless power-supply, here's some information about it:


+5V = 26,0A
-5V = 0.5A
+12V = 15,0A
-12V = 0.5A
+3.3V = 22.0A
+5VSB = 2.0A

My other hardware:
-Amd X2 5000+
-4x 512MB DDR2 SDRAM
-Asrock motherboard (don't know witch one anymore, but it doesn't matter)
- 1 SATA HDD at 7200RPM
- 1 DVD burner
- 1 80mm fan

I ran a test witch Extreme Power supply calculator lite:
Recommerd PSU wattage is 310 Watt (at 100%)

PS: I'm sorry but my english isn't that good...

Will it work?
a b U Graphics card
April 20, 2009 7:35:07 PM

Possibly, but it's not recommended. These are the requirements listed on AMD's web site:

ATI Radeon™ HD 4850 System Requirements
* PCI Express® based PC is required with one X16 lane graphics slot available on the motherboard
* 450 Watt or greater power supply with 75 Watt 6-pin PCI Express® power connector recommended (550 Watt and two 6-pin connectors for ATI CrossFireX™ technology in dual mode)
* Certified power supplies are recommended. Refer to for a list of Certified products
* Minimum 1GB of system memory
* Installation software requires CD-ROM drive
* DVD playback requires DVD drive
* Blu-ray™ playback requires Blu-ray drive
* For a complete ATI CrossFireX™ system, a second ATI Radeon™ HD 4850 graphics card, an ATI CrossFireX Ready motherboard and one ATI CrossFireX Bridge Interconnect cable per graphics card (included) are required

Also, 15A on the 12V rail seems a little low. If it is a no name PSU, do yourself a favor and purchase a known good model PSU.
April 20, 2009 7:44:59 PM

thanks for your reply, il'l just try, and if it doesn't work well I'l just buy a new one
Related resources
April 20, 2009 8:31:00 PM

jv8muts I believe the 4850 uses 18 amps on the 12 volt line.the 400 would work for awhile but it also say it recommends at least a 450 with 18 also have to consider the other parts in the pc drawing off that 1 12 volt 15 amp line.If it was me I would go with at least a 500 or 550 corsair or pc power & cooling.psu power every thing in the pc and yes a good one makes all the different s.hope this helps you out
a c 139 ) Power supply
a b U Graphics card
April 20, 2009 9:42:27 PM

Let us know how you make out after you give it a try.
a b ) Power supply
a c 365 U Graphics card
April 20, 2009 11:57:02 PM


Based on what you listed for the PSU, I do not recommend the HD 4850 since it consumes 110w under load. 15A on the 12v rail is relatively weak, that means it can only provide 180w on the 12v rail (15A x 12v).

That means you have 70w left to power the CPU, fans, DVD drive and hard drives. The 65nm Athlon 64 X2 4800 consumes 78.5w of power under load, so your X2 5000 will consume more. If you have the 90nm X2 5000, then your CPU consumes 111.5w of power.

Power Consumption sources:

Do not attempt to play any games until you replace the power supply as the computer will attempt to draw more power than the PSU can provide. Possible results:

2. PC freezes.
3. PC shuts down.
4. PSU fails.
5. PSU fails and an electrical spike occurs which flows through your PC potentially killing at least one other component with a very slight possibility all components will be destroyed and you will need to build a completely new PC.

I recommend the OCZ StealthXStream OCZ500SXS 500W which is selling for $50 after a $10 rebate. It is a good, reliable PSU and it has free shipping.
April 22, 2009 3:02:55 PM

It works, only when I start playing a game, It just shut's I'm going to buy a new PSU
June 10, 2009 2:13:16 AM

You should be fine im running with 500w psu and all my other pieces use like twice as much power, ive got a quad core cpu (phenom II 940 1.5v, 2x 7200 hdd, 3 120mm fans two LED 2 sticks 2gb 1066mhz lots of more stuff and im fine
June 10, 2009 2:30:03 AM

amateuruser said:

would the above psu work for the 4850? they are recommending 550W for ATI CrossFireXTM technology in dual mode?? can i get by with a 500W supply if i am connecting the pc to the monitor and the hdtv at the same time?

here is my mobo

a 500w is just fine since when they're saying 550w for crossfire, it means thats 2 cards running together. each card has 3 vid outputs, so if youre running one card then yes 500w is perfect for using a monitor and hdtv