Cortex M3 doesn't have an MMU so it won't run Linux or other desktop style operating systems. Generally they are programmed 'on the bare metal' or with a fairly lightweight RTOS. So depending on what duaneb wants to do it may not be appropriate.

If the idea is just "find out how well my code runs on a slow machine" a OpenWRT box is probably a decent bet. They are often MIPS core based but when programming in a high level language that doesn't really matter.

Good idea. As an embedded guy I don't always assume "testing my code" means running it on Linux.

Well, in this case he speaks of ARM as being the slow option. It seems safe to assume he's coming from x86, PPC, et al.

There are corner cases like DSP and high speed FPGA's, but I'm not aware of any general-purpose embedded chips that make ARM look slow.

Of course, this is only my opinion, having spent the majority of my time with embedded devices at or below 1MHz. Those 72MHz ARM cores are speed demons in comparison!

It's all relative.

The first few ARM chips ran at 4MHz and gave a 12MHz 80286 a severe run for its money.

We're now at 100's of times faster...

You can run Linux just fine on cortex-M3 without MMU (see http://uclinux.org/).

I think the $25 price point is a major draw. Your example board with fewer features is $60...

...and no Broadcom subsidy.

[EDIT] Am I wrong?

I don't know whether the board is subsidized or not, but I suspect most people don't care why it's as cheap as it is.

Yes, you're wrong. We don't get a subsidy or any other special treatment from Broadcom; they are helping us in allowing us to purchase chips in much smaller numbers than they'd usually consider, though. They're also very happy for their engineers to volunteer on the project (we have four or five who chip in) - outside work hours.

I don't get it? Are you saying that Broadcom are paying rpi to have the chips?

That's one way to think about it. Here's another: if you were actually able to get this chip from Broadcom (you're not), and asked for a 10K lot (you can't), do you think the price would let you achieve a $25 BOM?

What's the up side for broadcom though?

Publicity and maybe a tax write-off.

Cortex M3 is an excellent microcontroller, but not much more. It critically lacks a memory manager, meaning it can't run Linux or other full-featured operating systems. You also run into severe memory/flash limits.