18A on the 12V rail enough for an X1950PRO?

[Sylvan]

I am considering upgrading my video card but have a question about amperage requirements on the 12V rail. First, some background. Here's what I have powered by SeaSonic SUPER SILENCER-300W ATX12V Power Supply:

AMD Athlon 64 X2 4200+ 2.2GHz
ASRock 939Dual-SATA2 Motherboard
2x Crucial 512MB RAM
ATI Radeon 9600 All-in-Wonder Video Card (fanless)
Sound Blaster X-Fi Sound Card
Pioneer 16X DVD±R DVD Burner DVR-111D
SAMSUNG SP2504C 250GB 7200 RPM
SAMSUNG SP1614C 160GB 7200 RPM

Never had any trouble. Under the specification for the Radeon X1950 Pro video card I am interested in it says:

http://ati.amd.com/products/radeonx1950 ... specs.html

Connection to the system power supply is required:
* 450-Watt power supply or greater, 30 Amps on 12 volt rail recommended (assumes fully loaded system)

Seasonic rates the SS-300W to 18A on 12V1, and the 350W to 19A. So at first glance it looks like the PSU won't cut it, but Mike C posted http://www.silentpcreview.com/article28-page4.html a system with the X1950 XTX being run by the Seasonic SS-350W. I'm a little leary of just ignoring ATI's 'requirement', but I also recognize it as obviously too large. So, can I get some more opinions here? Is 18A on the 12V rail enough for an X1950PRO in my system?

[Redzo]

I'm a little leary of just ignoring ATI's 'requirement', but I also recognize it as obviously too large

Thats becouse ATI have to consider milions of poor quality,no name 500W PSU that in real world dont deliver even half of that power...

I think you will be just fine. I dont see how that system (even if it was fully loaded) could go over 250W....
Get the card and enjoy it

[Elixer]

My logic:

12V*18A = 216W

X1900 series have a max power draw of ~130W
Athlon 64 Series processor that you have I'm guessing has max power draw of 65W

So adding them = 195W
Add in CD drive at full speed plus hard drives at full seek (which also draw mostly from the 12V line) and you're right on the edge of the limit from the 12V line

However if you look at the real maximum power draw you should be fine. Also the X1900 series you want doesn't draw as much as the top of the line model. I think you should be fine. I wouldn't recommend a power supply with only 18A on the 12V line for that system, but it should be fine.

Edit - nevermind. This will work no problem. If a power supply with only 19A on the 12V line can run a Pentium D + X1900 no problem, then you should have absolutely no problem running your athlon with "only" 18A. The Pentium D is a much more power hungry processor then that athlon.

[mcoleg]

it should be fine but it's an old fashioned psu that is not made to run current systems.

since it's cutting it pretty close, all will basically depends on how well you maintain that psu. let it get full of dust or exhaust too much heat through it and the psu will loose efficiency, thus working harder than numbers indicate.

[kater]

My logic:
X1900 series have a max power draw of ~130W

Yes, if you mean X1950XTX. No, if you mean X1900Pro which needs only 70-75W.

18A will be fine, as the CPU will also consume app. 70W. HDD - <10W. ODD - 15W while burning.

[Sylvan]

So I went to try out wattage and 12V calc at http://web.aanet.com.au/SnooP/psucalc.php and it confirmed what folks are saying. SnooP estimates:

85W AMD Athlon 64 X2 4200+ 2.2GHz
66W Radeon X1950 Pro

After entering in the memory, and drives (no places for a sound card) it finishes with a recommendation of 256W and 17.3A on 12V line for a 'decent brand' PSU. So, yeah, while I wouldn't buy this PSU now (couldn't anyway), I really like it (it's quiet) and don't want to spend money if I don't have to.

I've been reading about the switch from 20pin to 24pin power headers and the increasing reliance on the 12V line. My mobo (and PSU) has one of the older 20 pin connectors and the 5V line is 30A! Presumably some percentage of the CPU power will come from there and put even less load on the 12V. The X1950PRO does require a external power connection, which with this PSU would have to be provided through an adapter.

[kater]

A sound card needs <5W (5V rail, I belive) so it's not a big deal.
Your RAM is most probably on 3.3V. Some chips (fast & OC'ed) will need. Again, we're talking about <5W per chip, unless you need it for record breaking OC.
The additional 4 pins in the big ATX connector are not really necessary, especially if your CPU is not a power hog (yours isn't). Sure, better to have, yeah, but you won't see the difference unless (again) you're into serious OC. I'd say you can safely run your rig w/o the 20>24 pin thingy. It only adds more spaghetti in your box

[Sylvan]

Well, I went ahead and got the card. It seems to be running fine in my rig.
Heckuva upgrade from an AIW 9600. Runs Oblivion beautifully on 'ultra high' settings, maybe 35-40 fps avg. Card is very quiet, even under load, and
runs cool.

When fan ramps up, it is the loudest thing in my case. I don't mind 'cause this is only during games, which, of course, make plenty of noise to cover it.

It came with a 4-pin to PCIE power cable that did fit. It silenced my X-Fi sound card until I shifted it to another PCI slot. I'm guessing maybe IRQs on mobo/OS (win XP); I doubt that it is because of this particular video card. My mobo has an AGP slot as well as a PCI-E slot, and this is the first time I've used the PCI-E slot, as my last graphics card was AGP. Even mentioning IRQs may show my age, but I read somewhere that PCI-E slots can cause cause conflicts, and moving my sound card over one slot did fix the problem.

[continuum]

It's got dual +12v out, traditionally +12V1 goes to the main ATX connector and peripherials, +12V2 goes to the ATX12V connector... although that's often different these days.

Either way, as you found, I wouldn't have expected any problems...