EDIT: After reading the AT review this is all I could find:
"Shifting gears, let’s talk about the SSD controller. Along with supporting NVMe, Apple’s SSD also supports a fairly wide PCIe x4 connection. Somewhat surprising it’s only clocked at 5 GT/sec (PCIe 2.0 speeds), but it’s unclear at this time whether that’s a controller limitation or an intentional design decision by Apple (update: It's a Core M limitation). Even at 5 GT/sec, an x4 link means there’s 2GB/sec of bandwidth in each direction, which is far higher than how quickly the SSD can read or write."
Appears Core M is limited to PCI-E 2.0 speeds, but apparently that's still plenty of bandwidth for the NAND, so I guess PCI-E 3.0 can't account for the difference between the Pro/Air and 12" MB. Maybe it's the custom Apple SSD controller just not being up to snuff compared to the over the counter controllers in the Pro/Air?
Original Post: Just curious if anyone has any in-depth knowledge as to why the SSD in the 2015 12" Macbooks are slower than the 2015 Pro and 13.3" Air models?
Seems the average blackmagic bench speeds are 450/775 MB/s write/read for the 12" MB.
While the Pro and 13.3 Air both have similarly performing 620/1200-1300 MB/s drives.
I know the NAND modules are soldered to the board on the 12" MB, while the Pro and Air both have PCI-E interface drives. But I don't see how that necessarily translates to lower performance. Not sure if maybe the core M or the motherboard chipset they're using offers less available PCI-E lanes? Or are they just using cheaper NAND? Not sure why they'd go with lower quality NAND in the 12" MB than the 13.3 Air, though?
So does anyone know the deal?
"Shifting gears, let’s talk about the SSD controller. Along with supporting NVMe, Apple’s SSD also supports a fairly wide PCIe x4 connection. Somewhat surprising it’s only clocked at 5 GT/sec (PCIe 2.0 speeds), but it’s unclear at this time whether that’s a controller limitation or an intentional design decision by Apple (update: It's a Core M limitation). Even at 5 GT/sec, an x4 link means there’s 2GB/sec of bandwidth in each direction, which is far higher than how quickly the SSD can read or write."
Appears Core M is limited to PCI-E 2.0 speeds, but apparently that's still plenty of bandwidth for the NAND, so I guess PCI-E 3.0 can't account for the difference between the Pro/Air and 12" MB. Maybe it's the custom Apple SSD controller just not being up to snuff compared to the over the counter controllers in the Pro/Air?
Original Post: Just curious if anyone has any in-depth knowledge as to why the SSD in the 2015 12" Macbooks are slower than the 2015 Pro and 13.3" Air models?
Seems the average blackmagic bench speeds are 450/775 MB/s write/read for the 12" MB.
While the Pro and 13.3 Air both have similarly performing 620/1200-1300 MB/s drives.
I know the NAND modules are soldered to the board on the 12" MB, while the Pro and Air both have PCI-E interface drives. But I don't see how that necessarily translates to lower performance. Not sure if maybe the core M or the motherboard chipset they're using offers less available PCI-E lanes? Or are they just using cheaper NAND? Not sure why they'd go with lower quality NAND in the 12" MB than the 13.3 Air, though?
So does anyone know the deal?
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