Contribute
Register

[Guide] 10.11+ USB changes and solutions

Status
Not open for further replies.
Its a Samsung 850 Evo in the cheapest possible ($10) usb 3.0 enclosure... I wouldn't be surprised if the little sata controller on it was only sata 2.

[EDIT] It seems if I want to buy a new one, the best choice would be USB 3.1 Gen1 with 'USAP' signalling feature. Since SATA III is limited to 6GBPs and the 10GBPs enclosures costs double for not very much extra speed / performance. That is for only a single drive.
 
Last edited:
dreamcat said:
Its a Samsung 850 Evo in the cheapest possible ($10) usb 3.0 enclosure... I wouldn't be surprised if the little sata controller on it was only sata 2.

[EDIT] It seems if I want to buy a new one, the best choice would be USB 3.1 Gen1 with 'USAP' signalling feature. Since SATA III is limited to 6GBPs and the 10GBPs enclosures costs double for not very much extra speed / performance. That is for only a single drive.
Click to expand...
A 5 Gb/sec USB port will limit an SSD's speed to about 412 MB/s write, 428 MB/s read. I used a raid of 2 SSD's in a 10 Gb/sec enclosure for that test.

A single SSD can go as high as 417 MB/s write, 497 MB/s read. That's with a PCIe gen 2 x4 SSD card (Tempo SSD Pro Plus) in my old Mac Pro 2008 in a gen 1 slot (1000 MB/s max). It should be more like 460 MB/s for write according to Sonnet.

So you'll loose only about 70 MB/s from not using a 10 Gb/sec enclosure. That's 14% of 500 MB/s. The Samsung 850 Evo might be faster than my SSD but maybe not since most current SSDs are limited by the SATA III interface anyway. Look at other benchmarks (ignore specs).

If you want to go faster, you have to make sure the actual controller in the enclosure can do the full 6 Gb/s. The Tempo SSD Pro Plus uses two Marvell 88SE9182 "2-port SATA III PCIe 2.0 x2" (1000 MB/s each). Some other controllers may be only PCIe 2.0 x1 (500 MB/s). I guess this can't be discovered without testing or physical examination, so look for benchmarks. This is easier with PCIe and Thunderbolt devices, since you can examine the IO Registry to get the controller information. I don't think you can do that with USB devices.
 
joevt said:
A 5 Gb/sec USB port will limit an SSD's speed to about 412 MB/s write, 428 MB/s read. I used a raid of 2 SSD's in a 10 Gb/sec enclosure for that test.

A single SSD can go as high as 417 MB/s write, 497 MB/s read. That's with a PCIe gen 2 x4 SSD card (Tempo SSD Pro Plus) in my old Mac Pro 2008 in a gen 1 slot (1000 MB/s max). It should be more like 460 MB/s for write according to Sonnet.

So you'll loose only about 70 MB/s from not using a 10 Gb/sec enclosure. That's 14% of 500 MB/s. The Samsung 850 Evo might be faster than my SSD but maybe not since most current SSDs are limited by the SATA III interface anyway. Look at other benchmarks (ignore specs).

If you want to go faster, you have to make sure the actual controller in the enclosure can do the full 6 Gb/s. The Tempo SSD Pro Plus uses two Marvell 88SE9182 "2-port SATA III PCIe 2.0 x2" (1000 MB/s each). Some other controllers may be only PCIe 2.0 x1 (500 MB/s). I guess this can't be discovered without testing or physical examination, so look for benchmarks. This is easier with PCIe and Thunderbolt devices, since you can examine the IO Registry to get the controller information. I don't think you can do that with USB devices.
Click to expand...

Let's try to limit off-topic content in this thread.
Thanks.
 
Hi Rehabman. Ive got a problem with USB on my Z77-DS3H system. I renamed EHC1 to EH01, EHC2 to EH02 and XHCI to XHC but the problem is at the login screen it takes awhile for my Apple Mouse and Keyboard to connect. Would you be able to check my USB configuration please.
 

Attachments

  • DSDT.aml
    40.2 KB · Views: 106
  • Jack’s iMac.ioreg
    4.4 MB · Views: 127
VoiletDragon said:
Hi Rehabman. Ive got a problem with USB on my Z77-DS3H system. I renamed EHC1 to EH01, EHC2 to EH02 and XHCI to XHC but the problem is at the login screen it takes awhile for my Apple Mouse and Keyboard to connect. Would you be able to check my USB configuration please.
Click to expand...

Read post #1, "Problem Reporting".
 
VoiletDragon said:
I thought you can't mix a SSDT with a DSDT.
Click to expand...

There is no limits on adding add-on SSDTs when you have a patched DSDT.

In fact, it is very common. The power management SSDT (output from ssdtPRgen.sh) is something almost all of us are familiar with.
 
RehabMan said:
There is no limits on adding add-on SSDTs when you have a patched DSDT.

In fact, it is very common. The power management SSDT (output from ssdtPRgen.sh) is something almost all of us are familiar with.
Click to expand...

Okay thank you mate :) I just wasn't sure if you could mix a SSDT for USB with a DSDT. Thank you for your help I will get on and customise the SSDT. Your the best :)
 
Status
Not open for further replies.
Copyright © 2010 - 2024 tonymacx86 LLC
Back
Top