Linked by Thom Holwerda on Tue 15th May 2012 14:05 UTC
Hardware, Embedded Systems "As the Raspberry Pi started to ship the Sinclair ZX Spectrum turned 30 years old, and comparisons were being made between the two and their role in providing access to affordable computer hardware. Given the phenomenal advances in computing since the birth of the ZX Spectrum, I thought it might be fun to compare the Raspberry Pi with a computer that was closer to the state of the art at around that time, and to see if the Raspberry Pi could fill its shoes..."
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RE[7]: Yeah,
by zima on Wed 16th May 2012 14:52 UTC in reply to "RE[6]: Yeah,"
zima
Member since:
2005-07-06

Though, IIRC, you also planned to use R-Pi with MAME ...that's very about CPU cycles ;p

Reply Parent Score: 2

RE[8]: Yeah,
by Morgan on Wed 16th May 2012 15:24 in reply to "RE[7]: Yeah,"
Morgan Member since:
2005-06-29

Yep, that's one of my planned projects. But from my understanding the RPi is more than capable of that. Its framerates in Quake 3 are almost as good as a Pentium 4 desktop PC, which is severe overkill in MAME. Granted, it's hard to compare an X86 system to an ARM system, but I would think if it could handle a 2000 era 3D game, it could easily emulate 80s and 90s arcade hardware.

Reply Parent Score: 2

RE[9]: Yeah,
by Neolander on Wed 16th May 2012 18:22 in reply to "RE[8]: Yeah,"
Neolander Member since:
2010-03-08

Be careful with that comparison though. MAME is mostly about CPU, whereas I would expect Quake to be more GPU-hungry than CPU-hungry, like other hardware-accelerated 3D games.

The reason why this difference matters is that the Raspberry Pi uses a SoC that has a very weak CPU by modern standards, but tries to compensate for it with a good GPU.

To quote http://www.raspberrypi.org/faqs...

"Overall real world performance is something like a 300MHz Pentium 2, only with much, much swankier graphics."

(PS : Could a hardware guy please explain me how x86 CPUs manage to do twice more stuff per clock cycle than ARM CPUs, if we are to trust these numbers ?)

Edited 2012-05-16 18:31 UTC

Reply Parent Score: 1

RE[9]: Yeah,
by zima on Tue 22nd May 2012 23:59 in reply to "RE[8]: Yeah,"
zima Member since:
2005-07-06

But from my understanding the RPi is more than capable of that. Its framerates in Quake 3 are almost as good as a Pentium 4 desktop PC, which is severe overkill in MAME. Granted, it's hard to compare an X86 system to an ARM system, but I would think if it could handle a 2000 era 3D game, it could easily emulate 80s and 90s arcade hardware.

Not so (and P4 isn't "severe overkill"): http://mamedev.org/devwiki/index.php/FAQ:Performance

Not only MAME is almost exclusively about CPU (vs. hardware accelerated 3D* in Q3, as Neolander points out), it hardly even strives for speed - not at the cost of increasing accuracy: it slows down over time (so you might have some better success with ancient versions of MAME; but don't expect too much)


Plus, while MAME devs eschew optimisation hacks, they might be used to x86 in their coding practices... and as far as performance goes, MAME is a sort of "shitty" code (deliberately, for faithful emulation and long-term viability of maintainable codebase) - features of modern x86 (advanced branch prediction, huge caches, memory bandwidths) help with such.


And as far as rigorously comparing x86 to ARM ...yeah, hard to come by. I stumbled only on http://coremark.org/ where:

Atmel AT91RM9200 180, an ARM9TDMI, gets 1.63 Coremark/MHz

ARM ARM1176JZ-S 1 gets 2.08 (curiously, that is an FPGA simulator ...but with RAM at the same speed as the CPU, that should help IPC - ~2 might be the upper limit of ARM11, especially since there's a Cortex-A8 nearby)

P4 gets 1.67 or 2.22 (with 2 threads and HT) - so probably quite comparable overall with ARM11 in IPC (and trampled down by most ~recent x86 CPUs), but of course with much higher clock.



* MAME hardly can benefit from 3D acceleration, if you think about it - not only most games are 2D with very different drawing methods between them and only some are 3D ...the latter also with very diverse approaches to creating 3D gfx (not even based on triangles, for example). Plus that goal of accuracy vs. the typical state of 3D drivers.

PS. And RISC vs. CISC that you mention nearby isn't really it - there are RISC CPUs with high IPC (paying for that also with high complexity and power usage). Plus, that RISC vs. CISC is mostly in the past, hard to find pure designs nowadays ;)

Edited 2012-05-23 00:19 UTC

Reply Parent Score: 2