5 ms·
Similarly to how dual channel memory is faster than single channel. Now you can do dual channel with a single stick, or maybe even quad channel with 2 sticks. I
by 0-_-0 6y ago
Similarly to how dual channel memory is faster than single channel. Now you can do dual channel with a single stick, or maybe even quad channel with 2 sticks. I believe it should be otherwise transparent to the rest of the system.
- aidenn0 6y agoI think that's wrong. Going from 1 64-bit channel to 2 32-bit channels has the same throughput per clock (or even slightly lower if the per-transaction overhead is paid separately on each channel).
- wmf 6y agoYes, but they also doubled the clock.
- aidenn0 6y agoWhich doesn't answer the question of "why didn't they just double the clock without reducing the bus width" but your answer to the original question sums that up nicely.
- crote 6y agoWell, you could just increase the clock, but it doesn't really gain you anything. G.Skill already has the F4-4800C18D-16GTRS which runs at 4800Mhz. Is it fast? Not really. The F4-3800C14D-16GTZN running at 3800Mhz is actually faster in practice because you're limited by the memory module's latency. Increasing the clock just makes it a lot harder for motherboard and CPU manufacturers to support those speeds, but on its own it doesn't really gain you a lot of speed.
- crote 6y agoBut memory is latency-limited, not bandwidth-limited. The channels are idle quite a lot of the time. So you go from REQUEST1---------RESPONSE1-REQUEST2---------RESPONSE2 to REQUEST1---------RESPONSE1RESPONSE1 REQUEST2---------RESPONSE2RESPONSE2 Each request individually is slightly slower, but the total bandwidth is greatly increased.
- mjw1007 6y agoI think SDRAM can do REQUEST1-REQUEST2---RESPONSE1-RESPONSE2 can't it?
- crote 6y agoYes it can! But, unless I'm mistaken, only within the same bank. This means you can basically only do this for sequential access, not random access. And there's still a non-zero latency between the responses, so it's still slightly slower than doubling the channels.