Comment on How much does storage speed affect your games?
spit_evil_olive_tips@beehaw.org 5 weeks ago
short answer: buy NVMe. plug it directly into your motherboard, don’t use an enclosure. forget about wonky RAID0 crap.
longer answer:
SATA SSDs (which you say in the comments below are all you’ve got) are an evolutionary dead-end. they’re SSDs pretending to be very fast hard drives. they end up being bottlenecked by the assumptions that the SATA protocol makes about how fast a hard drive can be.
look at this chart for example. SATA (AHCI) limits a device to having 32 commands queued up at once, which means the operating system needs to jump through hoops in terms of maintaining its own queue of pending reads & writes and issuing them to the device as queue space becomes available.
NVMe raises that limit to 64k, which for any non-server workload is effectively unlimited. the NVMe drive can respond to IO requests pretty much as quickly as the OS can dispatch them.
if you want to know more nitty-gritty details, Scaling ZFS for NVMe is an interesting talk, much of it isn’t specific to ZFS, but instead is about how NVMe devices are so fast that they’re forcing filesystem developers to rethink long-standing assumptions about drives being slow.