On Wed, 19 Feb 2014, Andrew McGlashan <[email protected]> wrote: > On 19/02/2014 12:51 PM, Toby Corkindale wrote: > > Well, it has 16GB of storage, 2GB of RAM and a dual-core 1.7 GHz ARMv7 > > CPU, so it's not all that constrained. > > Also, keep in mind that an ARM running at 1.7 GHz is nothing like an x86 > chip running at that speed. There is the whole RISC (ARM) vs CISC (x86) > situation to consider. > > On some tasks RISC is far superior, but because of the reduced > instruction set (RIS par of RISC), it may take more cycles to do some > things and therefore those tasks take longer and potentially drain the > battery quicker. If you are selective where you run those tasks, then > you can choose the right tool for the job, ARM not being right for such > particular tasks.
http://en.wikipedia.org/wiki/ARM_architecture#Instruction_set The ARM instruction set doesn't seem that reduced. There's the Thumb instructions, SIMD, Jazelle, and lots of other complications. Also the original RISC concept was based around the idea of a super-scalar processor being necessary to take advantage of linear reads of RAM. But for a long time all forms of main memory access have been slow when compared to a CPU. Modern Intel CPUs have as much as 20M of L3 cache to deal with this and CISC features such as a variable instruction width are better in this regard (which is why they have Thumb). http://vr-zone.com/articles/forget-benchmarks-arm-uses-real-life-gaming- performance-prove-beats-intel-video/59935.html A quick Google search didn't turn up any good micro-benchmark results comparing ARM and Intel CPUs. But the above article is interesting, it compares tablets based on ARM and Atom CPUs and shows the ARM tablet winning. Even though it's difficult to compare CPUs I think that showing a 3D game performing well is an indication that the device has adequate CPU performance for most workstation tasks. > At then end of the day, comparing ARM with x86 is like comparing apples > with oranges. Or perhaps more so in the computing world, Motorola vs > Intel. For many years Apple made use of Motorola to great benefit, but > they've moved to Intel for various reasons, not least of which, Intel or > x86 must have enough advantages over the Motorola offerings. Still, > Motorola is not AMD either; that's where the analogy breaks down somewhat. http://en.wikipedia.org/wiki/68000 http://en.wikipedia.org/wiki/80386 http://etbe.coker.com.au/2008/09/11/execmod-and-se-linux-i386-must-die/ The 680x0 ISA had some benefits, 8 general purpose registers vs 4 is a major difference. The lack of registers on i386 caused many performance problems and also drove the use of some hacks that weakened system security. The execmod problem probably wouldn't have occurred if we had all been using 680x0 CPUs. The advantage Intel had over Motorolla is a greater market share which gave them more money to spend on fabs. Making smaller transistors allowed bigger caches and higher clock speeds which gave better performance in spite of architectural issues such as a lack of registers. Also a significant amount of developer time has been wasted due to a lack of registers on i386. That would result in some combination of less development costs, less bugs, or more features. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/ _______________________________________________ luv-main mailing list [email protected] http://lists.luv.asn.au/listinfo/luv-main
