So I replaced the hard drive with a Crucial MX500 1TB SSD and the drive only operates in SATA 2 mode.  This appears to limit it to around 250 MB/sec.  There is no setting in the BIOS to change it.  Any way to make it use SATA III?
 

I just found out that the HDD itself is only running at SATA II mode according to Crystal Disk Info.

This does seem to be a problem. Is there any BIOS configurations we can modify to maximize the transfer rate?

I would assume the it is actually a SATA 3 interface which is limited in some way, do they still make SATA 2 interfaces? lol

Yes my SC17 the HD was upgraded to a SSD and I get SATA3 speeds, so EVGA really skimmped ou on including ony SATA2, as if no consomer planneld on upgrading eventually or immediately. Sure PS4 is Sata 2, who cares, but a premium SC15, that should at alt least have a 1070MQ by now, come on.   Eitheir way, Sata2 as a backup is plenty fast but very strange at this time and age  for a brand like EVGA, or any brand for that matter, even some of the newer consoles are now sata3.

vistarshook
SC15 specifically mentions 6G so....
https://www.evga.com/products/pdf/516-34-1833.pdf
so try upgrading RST driver. 
https://downloadcenter.intel.com/downloads/eula/27681/Intel-Rapid-Storage-Technology-Intel-RST-User-Interface-and-Driver?httpDown=https%3A%2F%2Fdownloadmirror.intel.com%2F27681%2Feng%2Ff6flpy-x64.zip
In Bios set Sata to ACHI, if not available, then unfortunately only by unlocking by Bios. It might be set to to IDE.
YOu can an also try to restore BIOS setttings to see if t get goes going at SATA 3 instead of 2.

I went into the BIOS settings and figured out the option for changing controller speed to SATA III just before your post .
 
The controller it self is capable of SATA III but the default (and hidden) option in the BIOS limited it at SATA II.
 
Yes, you do need to unlock the BIOS to change that configuration, although the edit is quite simple.
 
=============== DISCLAIMER =============
The steps below may result in possible hardware failure in
rare occasions. By following the instructions, you are fully
responsible for the outcome.
=====================================
 
Grab the tool called "AMIBCP" (from Google), open the BIOS file (in my case SC173106.bin, even though it is actually v1.06 for SC15), and modify "Access/Use" of "  -> Setup -> Advanced -> Hide Item" to "USER". (as shown below)

 
Save and flash the modified BIOS file and reboot into BIOS (by pressing F2 during booting). Follow the screenshots below (disable "Hide Item" to reveal all hidden items):
 

 
Save & Reboot and now your HDD/SSD should be able to reach full SATA III speed!
 
P.S. Not all hidden items work correctly, so tinker at your own risk. If you are stuck at a black screen after changing some settings, use the reset button at the bottom center of the laptop to reset all settings to default.

kaneorotar

starrbuck
Of course, as there is no reason for an HDD to run at over SATA 2 due to it doesn't go that fast.  It is likely hard-coded in the BIOS to use SATA 2 on the secondary drive.

So you mean the controller should automatically switch to SATA III when an SSD is attached?
 
I have no other laptops to test, but on my desktop I'm seeing Transfer Mode of "SATA/600 | SATA/600" for both HDDs and SSDs.

No, I was saying it is probably limited to SATA/300 because that's how it ships.  I will try the BIOS unlock posted above and report back.
 

starrbuck
So I have to uninstall Intel RST or it sets back to SATA/300.  I tried reinstalling but it goes back to 300 as well.
 
Also with Intel RST uninstalled I seem to be getting proper speeds but the CrystalDiskMark read tests will not run.  The write test runs fine and shows good speeds.
 

You had to uninstall RST after you unlocked the bios or you did that before messing with the bios?

So... For me, here is what I've tried...
 
I uninstalled Intel RST and reinitialized the new SSD after copying off all the data.  Then I got version 15.7 of the AHCI drivers from this link and installed them without installing the RST application.  Then I was able to copy all the files back and the drive remained at SATA/600.  However, something I have been unable to identify seems to be causing it to revert to SATA/300 again.

Weird.
 

I am on SATA3 in the BIOS and it stays that way.  It is just in Windows 10 when it goes back to SATA2.
 

Hi everyone,
 
I'll have our team look into this once we get back from the Memorial Day weekend.
 
Thanks for reporting this.  I'd advise against editing the BIOS before we've looked at it, but I'll let you all know when I have an update.

EVGATech_LeeM
Hi everyone,
 
I'll have our team look into this once we get back from the Memorial Day weekend.
 
Thanks for reporting this.  I'd advise against editing the BIOS before we've looked at it, but I'll let you all know when I have an update.

I look forward to hearing what you find out as I don't particularly want to modify my BIOS if I don't have to.

Thanks, Lee!!!

Gusbrz
Hi Lee,
 
I only see BIOS 1.06 from 4-16-2018 and prior releases. I don't see the Beta BIOS release.

Look for the Beta BIOS in the dropdown:
 

Lee, considering it’s a beta bios and not an official bios, does it void the warranty using this bios version? Also is warranty voided if the 1tb hdd is swapped out?