350watt PSU and Nvidia GeForce 9800GT

[Gnimble]

Hi everyone,

I bought the Nvidia GeForce 9800GT for my little brother to use on his system. Unfortunately, he has problems with the video card driving his HMDI only monitor and cannot get full HD resolution out of it so he gave it back to me.

I recently pulled a 350 watt power supply from my Dell Studio desktop to be used on my Compaq system. I was wondering if that power supply can drive the GeForce 9800GT?

Power supply specs:
Manufacturer: Bestec
Output:
+5V 18A
+3.3V 17A
+12VA 12A
+12VB 18A
-12V 0.8A
+5Vaux 2A

+3.3V & +5V 160W Max
+12VA & +12VB 300W Max

The eVGA 9800GT has a 6 pin power input. The box states "350 Watt or greater power supply with a minimum of 24 amps on the +12 volt rail."

It seems that I've met the minimum wattage, but what about the ampere? Do you add the +12VA +12VB together to get the total amp? Or does the highest number the max number as in 18A?

Thanks,
Gnimble

 

[OvrClkr]

You have to also take into consideration that the CPU/HDD/FANS draw power from the PSU as well. I am not going as far as saying that it won't work but I doubt you will have enough power for the whole machine.

 

[Gnimble]

Based on another thread I found, I think this power supply would satisfy the minimum requirements for the card. It said to divide the (+12VA and +12VB) 300W maximum wattage by 12 to get the total amp. When I did, it came out 25A which is just a tad bit above the 24A requirements.

But you're right regarding the total power draw of the systems. It is a dual core Athlon, 4GB RAM, 500GB hard drive that is currently powered by a 250W power supply. Since I'm short on cash, I'll give this a try and hope it wont' fry my new system.

Cheers,
Gnimble

 

[rolli59]

You got the calculation correct and it should work fine. Dell PSU's are rated for constant loads.

 

[OvrClkr]

I guess I was one of the unlucky ones, I had a 350w PSU that came with my XPS400 and it was not enough for a single GTS 250 unless I manually downclocked the card and of course I was not going to do that =(

 

[OvrClkr]

Not sure if it was a 350w or a 375w, all I know is that it was not doing the job. Replaced with an EA500 and all issues disappeared. I ended up selling the psu to my neighbor for 20.00$ since he needed to upgrade a 10 year old Dimension (250w PSU). The GTS 250 was the OC'ed model, not sure if that had anything to do with the power draw or not. When downclocked the PC was running fine, once I raised the clocks to stock levels the PC would shut down...