3 ms·
The three x4 links aren't sharing equally. One gets half bandwidth, two get a quarter each, when contended. If you're trying to read data off three drives, it's
by tedunangst 4y ago
The three x4 links aren't sharing equally. One gets half bandwidth, two get a quarter each, when contended. If you're trying to read data off three drives, it's going to appear like one is twice as fast. But then you try to reproduce reading data off one drive at a time, and they all work at the same speed.
- toast0 4y agoOk, but if you had 5 x4 drives before, one got full bandwidth from the cpu x4, and the other four would share (equally, I guess) on the chipset x4. Now, you'd get two on the uncontended cpu x4 lanes, and the three sharing (unequally, as you mention), seems slightly better that last time, but not an 'unusual departure' from the previous design; the CPU to chipset link is still very oversubscribed, but now, you can add a second oversubscribed chipset if you want, instead of having a choice between chipsets with different levels of oversubscription (or no chipset, only available in boards that don't expose most of the lanes)