Thank you but just 4GB memory supported with this CPU. now no differences between x64 and x32 ?Being able to address more than 4GB of physical memory is only one of the improvements the 64-bit architecture brings along. The other improvement is the 64-bit processing, which speeds up handling of large numbers. Also, when AMD created x86-64, they doubled the number of general purpose registers which should have some positive effects on performance as well.
Yes, that's certainly a possibility. With small computational loads utilizing 64-bit integers, I'd expect it to be faster. With more complex loads that require a lot of memory access, etc, the opposite could be true. The basic message is still that x86-64 is not all about accessing more than 4GB memory, though.A question for those talking about this CPU and getting better performance with a 64-bit OS: Is that a guarantee? It wouldn't surprise me if there was some relative variation when running 32 or 64-bit programs depending on the processor, especially at the low end. I would have thought that while a given processor can do 64-bit processing, it might be hobbled in such a way that it actually performs better at 32-bit processing instead (ignoring concerns about maximum addressable memory, etc).
64-bit code can be slower due to larger pointers and hence more data cache thrash.A question for those talking about this CPU and getting better performance with a 64-bit OS: Is that a guarantee? It wouldn't surprise me if there was some relative variation when running 32 or 64-bit programs depending on the processor, especially at the low end. I would have thought that while a given processor can do 64-bit processing, it might be hobbled in such a way that it actually performs better at 32-bit processing instead (ignoring concerns about maximum addressable memory, etc).
Being able to address more than 4GB of physical memory is only one of the improvements the 64-bit architecture brings along. The other improvement is the 64-bit processing, which speeds up handling of large numbers. Also, when AMD created x86-64, they doubled the number of general purpose registers which should have some positive effects on performance as well.
x86-64 introduced the 64-bit general-purpose datapath, with 64-bit execution units and general-purpose registers. It's also well known that the number of general-purpose registers was doubled from 8 to 16 as part of the x86-64 design. Why would you dispute this when it's so easy to check up on?SSE already added 128 bit registers and since the Pentium 3 days (albeit with 4 32bit floats). SSE2 (original Pentium-4) you could use 2 64 bit floats or ints. Increasing general purpose registers doesn't really have anything to do with x64 or not.
x86-64 introduced the 64-bit general-purpose datapath, with 64-bit execution units and general-purpose registers. It's also well known that the number of general-purpose registers was doubled from 8 to 16 as part of the x86-64 design. Why would you dispute this when it's so easy to check up on?
RAM isn't on-chip, though it's often found in the form of Package-on-Package: see step 6 hereThat is a system on chip. CPU, RAM, storage...all in one piece of silicon; the RAM is in that silicon and that is why only 4GBs is supported.