Timeline for Is there a good reason to run 32-bit software instead of 64-bit on 64-bit machines?
Current License: CC BY-SA 3.0
20 events
| when toggle format | what | by | license | comment | |
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| Apr 21, 2016 at 18:26 | comment | added | DocSalvager | @hyde As this Wikipedia article on 64-bit computing shows, 64-bit CPUs have 64-bit registers and 64-bit data and address lines. Thus, everything is moved in and out of the CPU 64-bits at a time. If only 32-bits (for example) are significant for a given operation, then only half the register is being used. The other half is wasted. Moving 8 bytes into the CPU would still require two fetches unless the compiler optimized the 32-bit code to collapse the 2 fetches into one. Two fetches take the same amount of time, regardless. | |
| S Apr 16, 2016 at 14:32 | history | suggested | Peter Mortensen | CC BY-SA 3.0 | Copy edited. Added some context. |
| Apr 16, 2016 at 11:27 | review | Suggested edits | |||
| S Apr 16, 2016 at 14:32 | |||||
| Apr 16, 2016 at 8:12 | comment | added | hyde | "64bit vs 32bit can easily double the memory requirements", not quite easily... Most programs have things other than pointers (such as code, strings and so on). | |
| Apr 16, 2016 at 3:31 | comment | added | user949300 | How can 64 bit "easily double" memory footprint? Maybe if every instruction is a pointer to a long constant, but that seems very unlikely. | |
| Apr 16, 2016 at 2:10 | history | edited | Ext3h | CC BY-SA 3.0 | added 8 characters in body |
| Apr 15, 2016 at 22:05 | comment | added | candied_orange | @Joshua Always existed? Did the pharaohs know this? | |
| Apr 15, 2016 at 20:34 | comment | added | Joshua | Incidentally, 32 bit alpha has always existed. See Windows NT Alpha. | |
| Apr 15, 2016 at 18:27 | comment | added | ElleJay | @BlueRaja-DannyPflughoeft on which platform did you test? On Linux (for me) 64-bit games perform usually better. | |
| Apr 15, 2016 at 17:38 | comment | added | jl6 | There is an additional benefit to simply picking one architecture and sticking to it: simpler development and testing. | |
| Apr 15, 2016 at 17:26 | comment | added | supercat | @BlueRaja-DannyPflughoeft: It's too bad that the scaled-segment concept used in the original 8086 was never extended to 32-bit segment registers, since even a very simplistic form with a fixed 16x scale factor would have allowed .NET to use 32-bit references to access 16-byte-aligned objects within a 256GB address space, and adding a little sophistication would have allowed memory to be partitioned into a small-object area with 16-byte alignment and a large-object area with 4096-byte alignment. | |
| Apr 15, 2016 at 17:26 | comment | added | kasperd | Saying 2GB/3GB per process is incorrect if we are talking AMD64 compatible CPUs. The AMD64 architecture allows 32 bit applications to use the full 4GB virtual address space as long as the kernel is 64 bit. | |
| Apr 15, 2016 at 16:24 | comment | added | BlueRaja - Danny Pflughoeft | For CPU-bound video games, in every case I've tested I've found that the x86 build performs better than the x86-64 build (examples: Starcraft 2, various Unreal Engine games, various .Net XNA games). I think it's a combination of better cache-coherency, plus more mature compilers for x86. | |
| Apr 15, 2016 at 16:16 | comment | added | Ext3h | @zwol No, 32-bit is not mandatory for ARM, and neither is 64-bit. There are 64-bit only ARM CPUs, while others support both 32-bit and 64-bit processes. | |
| Apr 15, 2016 at 16:13 | comment | added | zwol | @mucaho There certainly have been 64-bit-only CPU architectures, such as the Alpha and the IA64. Both of those are moribund, though. I don't know off the top of my head whether there are any currently produced 64-bit-only architectures - AArch64, maybe? Does anyone know whether 32-bit ARM is a mandatory component of that? | |
| Apr 15, 2016 at 15:54 | comment | added | mucaho | "The 64bit CPU architecture may not even support 32bit at all." Is this more of a theoretical concern, or does this exist in the world? | |
| Apr 15, 2016 at 12:28 | history | edited | Ext3h | CC BY-SA 3.0 | added 38 characters in body |
| Apr 15, 2016 at 11:21 | vote | accept | Drathier | ||
| Apr 15, 2016 at 11:16 | history | edited | Ext3h | CC BY-SA 3.0 | edited body |
| Apr 15, 2016 at 11:09 | history | answered | Ext3h | CC BY-SA 3.0 |