11/24/2023 0 Comments Sequential take 5 firmware![]() ![]() The 256GB drives are rated at 50,000 write IOPS, which is excellent. It's a similar story in random 4k access, with writes falling off dramatically with smaller drive capacities. That said, the Marvell 9174 doesn't rely heavily on compression technology to achieve its peak speeds, which means it's closer to and sometimes even faster than the SandForce SF-2281 when it comes to incompressible data transfer. In reality, it's a bit more complicated and the performance scaling isn't quite as linear. In that scenario, you can request a write to chip one and while waiting for that to complete, put another request to chip two. The problem here is that the controller sits idle during those cycles - but not if you have additional chips per channel. That's because each read or write request takes a certain number of controller cycles, let's say five or six cycles for argument's sake. So far so simple, but even if you have a chip for each channel, you don't have the optimal solution. ![]() If you have very few chips, you can't even populate each channel (typically, controllers have eight channels), and that means less bandwidth. Controller chips have a certain number of channels, attached to which are the memory chips. The explanation for the Marvell controller's fall off at smaller capacities (this applies to other controllers, too) is complex and involves a technique known as interleaving. But at best you're looking at about 300MB/s for writes, and that's only for 256GB and larger drives.The 128GB versions are nearer 200MB/s, with 64GB drives down around 100MB/s. Typical peak sequential read speeds of 500MB/s or more are obviously competitive with SandForce drives. By some of the headline metrics, it's a little off the pace compared to the SandForce SF-2000. Next up is the Marvell 9174, seen in Crucial's RealSSD M4, Corsair's Performance Pro series and a few others. But the length of time Intel took to release its own version of the SF-2281 hints that quite a tidy-up job was involved. Subsequent firmware releases appear to have cleaned its act up. Early drives based on the SF-2281 reportedly suffered from 'the blue screen of deathitus'. ![]() If the SF-2000 series has a weakness, it's stability. On the other hand, the SF-2281 is up there with the best when it comes to 4k random numbers, which roughly approximate the daily drive churn generated by a modern PC.Īll told, the SF-2281 is a controller that's at least competitive in all areas and relatively dominant in some. And the SandForce SF-2281 is competitive rather than dominant when reading incompressible data and especially writing it. Most of the really big file types, such as audio, video and images, are essentially incompressible. But it reflects real-world performance more closely than peak sequential transfer rates, especially when it comes to compressible vs incompressible data.įor starters, it's rare - in reality - to shunt around large quantities of compressible data. That may sound like a theoretical metric. It's also very competitive when it comes to 4k random IOPS. ![]()
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