BlingBlingArsch
Golden Member
i been reading reviews on A64 trying to get increase my knowloedge and i just dont get what this passage from: http://www.lostcircuits.com/cpu/amd_venice/4.shtml means.
"Added Support for Unequal Memory in a Single Channel
One issue that has plagued dual channel memory operation wherever it was implemented (except for the nForce2) was that within one channel, both memory slots needed to be populated with identical modules. In the case of the P4, this makes perfect sense in that the banks are simply combined to make a single 128-bit wide memory unit out of two 64-bit wide subunits. The sense in this case is the simplicity of the idea. On the other hand, regardless of which way one looks at it, the integrated AMD memory controller is a bit more sophisticated and can do more than a simple addition of 64+64.
Keep in mind also that the memory management unit, which is part of the actual CPU core performs virtual address mapping, meaning that virtual addresses that are unique on a per program basis can be translated to any kind of physical address within the memory array. Therefore all that is necessary is that the controller knows what memory devices are available where, in order to work in a dual channel mode. Arguably, this is a bit more complex than simply mirroring the physical addresses à la Intel over two separate channels but it also offers a much more flexible architecture with less redundancy because data are not read based solely on where they are in the array but rather based on whether they are needed or not. In practice, it depends on the application at hand whether there is a performance difference between the two methods, if there is a high locality of data, then the difference should be negligible."
Maybe iam getting it all wrong but does this mean that AMDs version of dual-channel is still working when i plug in for instance one 512mb and another 256 or 1024mb of Ram?
ty
"Added Support for Unequal Memory in a Single Channel
One issue that has plagued dual channel memory operation wherever it was implemented (except for the nForce2) was that within one channel, both memory slots needed to be populated with identical modules. In the case of the P4, this makes perfect sense in that the banks are simply combined to make a single 128-bit wide memory unit out of two 64-bit wide subunits. The sense in this case is the simplicity of the idea. On the other hand, regardless of which way one looks at it, the integrated AMD memory controller is a bit more sophisticated and can do more than a simple addition of 64+64.
Keep in mind also that the memory management unit, which is part of the actual CPU core performs virtual address mapping, meaning that virtual addresses that are unique on a per program basis can be translated to any kind of physical address within the memory array. Therefore all that is necessary is that the controller knows what memory devices are available where, in order to work in a dual channel mode. Arguably, this is a bit more complex than simply mirroring the physical addresses à la Intel over two separate channels but it also offers a much more flexible architecture with less redundancy because data are not read based solely on where they are in the array but rather based on whether they are needed or not. In practice, it depends on the application at hand whether there is a performance difference between the two methods, if there is a high locality of data, then the difference should be negligible."
Maybe iam getting it all wrong but does this mean that AMDs version of dual-channel is still working when i plug in for instance one 512mb and another 256 or 1024mb of Ram?
ty
