More cores, mostly. I tried using the Raspberry Pi with server software such as Owncloud or calendarserver. It just barely works, but it is still very slow. Like, response times upwards of four seconds.

Recent smartphone processors have since about doubled their clock speed and quadrupled the processor count. Even half that would bring response times below a second, which would be much appreciated.

There are quite a few quad-core, single-board, fanless ARM computers: utilite, wandboard, odroid, udoo, radxa.

I have two odroid U2 that I use for testing distributed and multithreaded code. One odroid core (exynos 4412 @1.7GHz ) is more than 8x as fast as the pi, for some numerical simulation code (ODEs). Storage is eMMC, so should be faster than the class 10 SD card in a Pi. It was very easy to get Linaro set up on them (for headless use, as compute servers). Recommend highly.

I use my two RPi for file serving, backups via rsync and btsync, limited web (one is at a remote location).

There's a utilite pro on order as well, but they are a bit backlogged, as I understand it. I'm looking forward to the 2x Gb eth (odroid is 100Mb) and faster bus and disk speeds.

These sites track new board and mini-pc releases:

http://linuxgizmos.com http://www.cnx-software.com http://liliputing.com/tag/mini-pc http://www.fanlesstech.com

Yeah, I could see why dropping that stuff on it would pretty much swamp it. Of course your running a giant PHP infrastructure [1] there which was built the way it was in part because memory and cpu cycles were "free."

What I'm saying is that you could implement the equivalent of OwnCloud and CalendarServer on the Pi knowing that it needed to be memory and CPU efficient, and no doubt get 300 - 500mS responses. But that would mean not using frameworks that start by assuming you have at least 1GB of memory free and can run an interpreter (PHP) on an interpreter (JS) on the actual code.

Looking at the code for these I think the biggest issue is memory for them. A 2G Pi would probably do what you needed, trying to swap on the Pi (especially if you do that to an SD card) makes it really really slow. Its better if you can swap to an NFS mounted file system, and even cooler if you can swap to a custom memory instance in another server :-)

[1] https://github.com/owncloud/core

FYI, proper SI nomenclature for milliseconds is ms, not mS :)

SI units are not capitalized unless they are someone's name, such as Pascal (pressure) or Newton (force) etc.

Try convincing a physicist that ms means millisecs and mS means milliSeconds. Casually remind them about the difference between bits and bytes and lament the unfortunate fact that textbook writers still don't give enough respect to the "forgotten units". Let the doubt sink in just a little bit.

http://images2.wikia.nocookie.net/__cb20100726071250/xkcd/im...

Its not really that slow; try different software. Low power means you need to be slightly efficient.

Well, for today's software, it kind of is slow. Its IPC performance is about 1 DMIPS/Mhz vs ~3.5 for the latest high-end ARM chips, which also have 3x the clock speed of RPi, and come in quad-core variety. Do the math. That's a 10x-40x delta. Of course such a board wouldn't cost $30 anymore, but they could still improve performance by at least 3x with another low-end, but more modern, CPU, even as single core, but even more as dual-core or quad-core. Even a single core Cortex A7 at 1.2 Ghz would be about 3x faster than Raspberry Pi (90 percent faster IPC * 70 percent faster clock speed).

Personally, I think they should wait until they can make a dual-core 1.5 Ghz Cortex A53 with 1 GB of RAM for $25, which may be possible by 2015, and maybe a quad-core 1.5 Ghz Cortex A53 one with 2 GB of RAM (and perhaps a few extra stuff), for under $50 (I would make it for $40-$45 so the total cost with shipping and whatnot still remains under $50 for most people, instead of going over that price point). A single core Cortex A53 at 1.5 Ghz (its stock clock speed) would be ~5x faster, and also 64-bit. By the way, Cortex A7 and Cortex A53 are both the true successors of the ARM11 CPU RPi is using, and they serve the same markets.

The $25-$50 market, is still probably their best market, since a lot more companies compete at the $100-$200 level.

Kind of slow, but the OP is talking about seconds in response time, something is going badly wrong. Software issues not CPU throughput. It doesn't help that IO is terrible, there is no point putting in a faster CPU without SATA and a bit more throughput overall.

They are in a great position for volume, so should be able to do better than the current choice that was suboptimal in so may ways. Not clear that the 64 bit stuff will be that cheap soon (plus porting code will take a while) but it depends when they are going to do something. Cheap is important.

i used to run Owncloud (php), which was ok for CalDAV and CardDAV, but the web interface was terribly slow. Now I run calendarserver for CalDAV/CardDAV (Python), which is fast for CardDAV (few data) and slow for CalDAV (a lot of data). I am also running Bittorrent Sync (binary blob, fast), and Time Machine backups (fast).

My conclusion: The Raspi is slow for serving with dynamic languages. Compiled stuff is fine.

As you would expect for a processor designed for embedded systems. Everyone trying to use this as a cheap LAMP server gets what they're paying for.