PSU for Rx460

[Aniruddha_3]

Rx460 can I run with a PSU of 450watts and 18A in the 12V rail.

 

[raisonjohn]

It depends on what your CPU is, what specific model your RX 460 is, and what other components you have that are/will be connected to the PSU.

 

[Aniruddha_3]

My Processor is intel core i3 3.2ghz 3rd gen no over clock
There are 1x ddr3 2gb +1x ddr3 4gb ram . total of 6 GB
1tb hard disk
A Asus M5A78 L mother board .
A 1080p Asus Rog monitor.

 

[raisonjohn]

Your i3-3210 would roughly draw 55W (based on its TDP). Your RAM's would draw around 5W. Your HDD would draw at startup somewhere within the 30W range. Other components (fans, USB, etc.) connected to your motherboard roughly at 100W (for headroom). So, without the GPU yet, you might look at just ~190W power draw so far.

The RX 460, depending on the actual/specific model you choose, can theoretically draw 75W or up to 150W of power. So, adding this to your current setup, you'd be looking at ~265W to ~340W of power at the +12V rail.

Now for that 450W PSU with 18A at +12V rail you mentioned, the 18A = 216W only (assuming 18A is a single rail PSU). That is definitely not enough. But you really have to check the actual PSU specs if that 18A you mentioned is just 1 rail out of 2 rails (or more). Your concern is the TOTAL COMBINED +12V RAIL output (not just the single rail among multi-rail).

For example, the Antec TP-450C (450W PSU) provides 20A on +12V1 and 20A on +12V2. The total combined power/amperage is 444W (or 37A). This PSU would be enough.

If the 18A ~ 20A is the total combined power/amps, then you should change your PSU.

 

[Aniruddha_3]

How can I know that my PSU has 2 rails or a single rail

 

[raisonjohn]

How can I know that my PSU has 2 rails or a single rail

Look at the markings at the side of your PSU or at the box or at their website specs.

Multi-rail (2 or more rails) should look like this (notice the +12V1 +12V2 +12V3...):

Single rail should look like this (notice only one +12V):

 

[Joshua French]

http://www.coolermaster.com/power-supply-calculator/
As long as the amp's check out.
There are adapters to merge rails if you want to do that. But single rails should have more amps on 1 rail compared to multi-rails on 1 rail