I know similar questions have been asked, but with different components and such, and different spec'ed PSU's, I just have to ask again, for I am considering an upgrade for my video device.
I am currently running a gateway DX4820 series computer with a 300W PSU. The card I hope to throw in is a Radeon 5670 (To replace an ole HD 4350). I have considered numerous times to upgrade the PSU to support the 5670, or even something higher-end, but have hesitated because of the way the case is designed, which seems to make it difficult to replace the PSU itself. The wires itself don't intimidate me, but there seems to be a lack of clearance to getting the PSU out without taking apart additional components (Giant air duct in the way).
Without going through unnecessary hassles, I am trying to determine if a PSU upgrade is absolutely necessary.
I understand that the Radeon 5670 draws a max of 75W, which is 6.25 amps off the 12V rails? The PSU I have right now has 8 Amps on its 12v1 rail and 14 Amps on its 12V2, making a total of 22 amps. The only components I have is 1 SATA Hard Drive, 3 sticks of DDR3 RAM, and my DVD/RW. No other PCI cards plugged in. My processor is a Q8200 2.33 quad-core.
Now, I know the 5670 states 400W PSU is recommended, but I am curious if this 300W PSU will handle it okay with the components I have?
Thanks for the reply. I might consider getting this card then...
I just have one more question; just to stick to the safe side. Since my PSU uses two rails, I read somewhere that the cpu normally gets the second rail to itself, which is more than it needs. Is this true? I've been playing around with 12V calculator and it says that my gaming draw will be about 6.1 amps (with the cpu on 12V2) on the 12V1 line (though i'd add a +- .5 or 1 to that figure). This does not appear to give too much headroom for an 8 amp output on the 12V1 line. Would it still work alright?