On SSDs and BlackMagic. What the EFI?

TidBITS Talk
1

We’ve had a bit of a lockdown computer reshuffle here at home, taking the enforced downtime to pass on a couple of old machines, buy slightly better ones, upgrade storage, review backups disks etc. Part of this fun has been comparing the performance of various components using BlackMagic Speed Test tool.
I was agreeably surprised at the performance of the boot SSD in my i9 27” iMac coming in at 1700 MB/s read and write, until a friend with a new MacMini did the same test and got a consistent reading of 2700 MB/s read and write.

The iMac has ‘better’ hardware in almost every way compared to the MacMini and the only difference I have been able to see, in comparing the System Reports is around the SSD itself, revealed in the NVMExpress record.

Mine, in the iMac:
Generic SSD Controller:
INTEL SSDPEKNW010T8:
Capacity: 1.02 TB (1,024,209,543,168 bytes)
TRIM Support: Yes
Model: INTEL SSDPEKNW010T8
Revision: 002C
Serial Number: BTNH94100Q2W1P0B
Link Width: x4
Link Speed: 8.0 GT/s
Detachable Drive: No
BSD Name: disk0
Partition Map Type: GPT (GUID Partition Table)
Removable Media: No
SMART status: Verified
Volumes:
EFI:
Capacity: 209.7 MB (209,715,200 bytes)
File System: MS-DOS FAT32
BSD Name: disk0s1
Content: EFI
Volume UUID: 0E239BC6-F960-3107-89CF-1C97F78BB46B

His, in the MacMini:
Apple SSD Controller:
APPLE SSD AP2048M:
Capacity: 2 TB (2,001,111,162,880 bytes)
TRIM Support: Yes
Model: APPLE SSD AP2048M
Revision: 717.100.
Serial Number: C079105002KJRXNA5
Link Width: x4
Link Speed: 8.0 GT/s
Detachable Drive: No
BSD Name: disk0
Partition Map Type: GPT (GUID Partition Table)
Removable Media: No
SMART status: Verified
Volumes:
EFI:
Capacity: 314.6 MB (314,572,800 bytes)
BSD Name: disk0s1
Content: EFI
Volume UUID: E783267B-A4C3-3556-B751-DBED770EB996

So his Mac Mini has an Apple SSD whereas my iMac has an Intel one. And though my Data volume is formatted APFS, the EFI portion seems to be Fat32. How? Why? It’s hard to find information about any of this and I wonder if anyone could shed any light?

What SSD do you have on board, from Apple, and should this make any difference? Needless to say I am gutted that his Blackmagic speed report appears to be so much better than mine!

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The speed difference can be from many possibilities. My first suggestion is that, because the internal multiple data paths possible, a similar SSD of larger capacity generally has higher read/write numbers than does a smaller capacity SSD.
Also, the Apple memory controller in the latest Mini is the T2 chip and may have optimizations not available in the Intel controller. The SSD memory chips and the T2 disk controller function together comprise an SSD drive configuration tightly controlled by Apple.
The EFI volume uses industry standard FAT32 format for supporting boot from many operating systems. It has no effect on post-boot system performance.