5 ms·
>Is it as fast as having more DRAM in all possible scenarios? Is it as fast as having more DRAM in any scenario?
by voldacar 6y ago
>Is it as fast as having more DRAM in all possible scenarios?
Is it as fast as having more DRAM in any scenario?
- zepto 6y agoObviously so based on Apple’s numbers.
- dogma1138 6y agoNot just Apple we have multiple other examples of when a unified memory pool outperforms larger non unified memory pools just due to the overhead of having to copy memory manage multiple memory address spaces with all the translation and lookups you need to do etc. We have cheap consumer SSDs today offering 5GB/s of read performance and more than enough I/O to satisfy caching.
- dogma1138 6y agoYes, and based on non Apple systems it’s faster than having much larger pools of non-unified memory. Essentially all the big compute vendors moving towards memory unification and cache coherent interfaces.
- voldacar 6y agoOk I misread the numbers somehow. This is interesting - I wonder what it means for the future of conventional desktop computing, when considering peripheral chips like GPUs that already have DMA capability
- dogma1138 6y agoGPUs are going above DMA, DMA still needs memcopy and or address space translations which adds latency slows things down, with unified memory in theory you have a single address space and cache coherency across everything which means you can operate at the maximum bandwidth of all interfaces without wasting any cycles.