Will mobile Llano FS1 APUs work in a FM1 motherboard?

[Aidman]

I thought I'd start a new thread about that fact there seem to be no FM1 APUs available with less than 65W TDP. It seems ridiculous to me that there are a whole range of Mobile FS1 APUs available with only 35W TDP that would be great for a Mini-ITX/HTPC setup but sadly these are only available in notebooks??

Currently I have a E-350 APU in my Mini ITX system which only has a 65W PSU, but I'd prefer something with a little more grunt for the odd game of Portal but obviously a Desktop Llano will push the TDP for the system above what my PSU can handle.

Does anybody know if it is possible to run a mobile Llano FS1 processor in an FM1 socket motherboard and if the mobile APUs are even available to buy separately?

[CAT-THE-FIFTH]

Not AFAIK.

Trinity might have lower wattage derivatives.

[DanceswithUnix]

The idle power usage will be the same whether mobile or desktop, you just need to cap the flat out power.

Undervolting can work it seems:
http://www.brightsideofnews.com/news...-by-3225!.aspx

and capping the cpu multiplier to drop the max frequency to laptop sort of speeds would get the max power down as well.

Would still take a very stripped down motherboard to get a system power down to 65W though. All those wifi etc ports suck power. If the platform is 40W at idle, you only have an extra 25W to play with at load

http://techreport.com/articles.x/21743/6

That 40W idle is at the wall I know, but I like to leave some margin in these things.

[CAT-THE-FIFTH]

It seems the second article uses the 100W A8-3850. A 65W A8-3800 would probably drop power consumption under load to around 90W to 100W:

http://techreport.com/articles.x/21730/2

However,a 760W PSU is being used so a DC-DC PSU would reduce the power consumed by a few more watts.

Edit!!

Some additional Llano A8-3850 undervolting figures:

http://www.silenthardware.de/2011/07...s-ist-moglich/

http://www.hardware.fr/focus/48/amd-...ervolting.html

[scaryjim]

The real problem with DC-DC PSUs is that they don't tend to have enough ampage on the 12v line. I couldn't run my undervolted Sempy 140 on a 90W DC board despite the total system power draw through a 250W PSU being < 60W, because the overcurrent protection tripped when the system started up. Now, my mobo is relatively heavy on the bells and whistles (ASUS 785G EVO), but I've never seen my at-wall power meter read over 60W on that system: nevertheless the overcurrent protection tripped on start up despite the PSU being rated for 5A (i.e. 60W) on the 12v line. So if you're running off only a 65W DC board, I'd find it very unlikely that you'd get away with even a heavily undervolted 65W APU...

[DanceswithUnix]

So I think we are saying casual Portal probably requires microATX?

Only game I play on my E350 is plants vs zombies. That rocks. And shoots peas

[Aidman]

Cheers DanceswithUnix I hadn't considered under-clocking/volting a desktop APU but that might just work ;-)

If I took a 65W A4-3300 for instance (2.5Ghz, 2 cores, 240 radeon cores) which is architecturally similar to the 35W A4-3320M (2Ghz, 2 cores, 240 radeon cores) and set the multiplier & voltage to the same levels as the latter do you think I'd achieve 35W TDP under load?

If I combine it with a low power ITX motherboard such as an ASRock A75M-ITX, the rest of my system consists of a 64Gb SSD drive and low voltage DDR3, do you think this system config would be lower that 65W? I guess I could always experiment with the level of under-clocking/volting to find the highest stable settings my 65W PSU can handle.

[scaryjim]

As I said earlier, I don't think you'll get the draw low enough not to over-current the 12v line on a DC-DC board, but I'd be happy to be proved wrong. I think it'd be a much better idea to get a 1U flex-atx PSU - e.g. http://linitx.com/product/12301 - and mod your case a little to fit it in. That way you'll *know* you can power your Llano setup...

[CAT-THE-FIFTH]

I would check this thread out:

http://forums.hexus.net/pc-hardware/...ing-build.html