help choosing the right fanless PSU

[eadmaster]

My actual setup:
- motherboard: Asus F1A75-M LE (NOTE: it has a 24-pin EATXPWR + 4-pin ATX12V connector)
- CPU: AMD A6-3500 (stock voltage and frequency)
- CPU heatsink: AMD stock
- case: NZXT Nemesis
- RAM: 1x Corsair CMZ4GX3M1A1600C9
- 1x 2,5'' HDD: SEAGATE FreeAgent GoFlex Portable 500Gb (connected via SATA)
- 1x 3,5'' HDD: Samsung EcoGreen F2 Hd103si 1TB
- PS/2 mouse and keyboard
- 1x USB SD card reader
- 1x USB gamepad
NOTE: no discrete video card plugged

Is it ok if i get an 80/90W PSU?
Is it ok if i get a PSU with a 20-pin connector instead o 24?

[CA_Steve]

Here's Anandtech's review of a Puget Sound PC with the A6-3500 and an 80W brick. You have two 3.5" drives which will consume a few watts more than the SSD and 2.5" drive in this setup. So, 90W should cut it..but you might consider 100W for some breathing room.

[eadmaster]

Thanks for pointing me there, the case used by the Purget System is an Antec ISK-110.
A 20-pin plug should be fine since i won't exceed the 10A ATX spec on each rail.
My only concern is the 3,5'' HDD may exceed the PSU rating for the 12V rail, so i'm trying to estimate that:
2A is required for the drive spinup + 5A for the rest of the system, so i guess the picoPSU-90 is not fine (rated 5A max).

Since it won't be installed in a space-constrained case, do you think using a bigger PSU board like this will help dissipate the heat better?

[edh]

My only concern is the 3,5'' HDD may exceed the PSU rating for the 12V rail

With the PicoPSU the 12V is a passthrough of the 12V input if I remember correctly. Therefore it is down to the size/quality of the AC/DC power brick which will influence this.

[eadmaster]

My only concern is the 3,5'' HDD may exceed the PSU rating for the 12V rail

With the PicoPSU the 12V is a passthrough of the 12V input if I remember correctly. Therefore it is down to the size/quality of the AC/DC power brick which will influence this.

In the "-WI" models the 12V input is not passed through. For the other models the manuals still report different max load ratings for the 12V rail:
1. PICOPSU-90 -> 5A
2. PICOPSU-120 -> 7A
3. PICOPSU-120-WI -> 6A
4. PICOPSU-150-XT -> 8A
I guess i should be fine with 2 and 4.

EDIT: the Winmate DD-24AX looks even better (rated 10A max)!