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DMM doesn’t release memory in SCSI mode

Posted: Sun May 10, 2020 12:04 am
by Yibo
Hi, I recently began to use Primo Ramdisk and find it’s a lot better than the previous one I used for a long time. But I do have a problem: on my main PC the DMM doesn’t release memory in SCSI mode at all, (in Direct-IO mode DMM works correctly and releases freed memory as expected, but unfortunately exactly as hinted in Direct-IO mode some applications I use don’t recognize the partitions created by Ramdisk). This issue exists only on this PC and only on Windows 7, I tried on this PC with Windows 10, it’s fine. I tried on my Laptop with Windows 7 and Virtual Machine with Windows 7, everything is fine. I’m pretty sure a reinstall of Windows 7 would solve the problem but it’s really the last resort. Is there any way I can find out what causes the problem? (I’m not using the compact mode and I don’t use disk image at all.)

A few info: This Windows 7 system is years old and went through two motherboard upgrades(Z77 to Z170 to Z370) but it works perfectly otherwise. I do use another Ramdisk program and virtual DVD Drive which may cause the problem(?), but they are also installed on my Windows 7 Laptop. I compared enabled Windows services between the PC, Laptop and virtual machine, nothing suspicious.

I would really like to buy one after the trial expired if this issue can be solved…

Thanks in andvance!

Re: DMM doesn’t release memory in SCSI mode

Posted: Tue May 12, 2020 6:21 am
by support
Do you use the latest version 6.3.1? Does the ramdisk volume formatted with NTFS file system?

Re: DMM doesn’t release memory in SCSI mode

Posted: Tue May 12, 2020 6:59 am
by Yibo
Hi, thank you for your reply! yes, i tried 6.3.1, and even found two older versions and tried them, all the same. Only on my main PC and only with this Windows 7 the DMM doesn't release freed memory, and yes, with NTFS....

Re: DMM doesn’t release memory in SCSI mode

Posted: Tue May 12, 2020 7:51 am
by support
I'm wondering this problem is caused by another application. Could you check followings?
1. Open the registry editor, and go to the branch:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e967-e325-11ce-bfc1-08002be10318}
Check the values in "LowerFilters" and "UpperFilters".

2. In the registry editor, go to the branch:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{71a27cdd-812a-11d0-bec7-08002be2092f}
Check the values in "LowerFilters" and "UpperFilters".

3. Open the command prompt with administrative privileges, type the command: fltmc instances -v x: , where x is the SCSI ramdisk drive letter. Check the output.

Re: DMM doesn’t release memory in SCSI mode

Posted: Tue May 12, 2020 7:46 pm
by Yibo
Problem solved, many many thanks!

I checked the values and compared them with the one on my laptop. What caused the issue was "iaStorF" in "LowerFilters" under "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e967-e325-11ce-bfc1-08002be10318}". It's a Intel driver for AHCI(in my case called something like„AHCI driver for Intel 300 series” under device manager), actually I have had least suspicion about this one, because there must be a lot Primo Ramdisk user having this driver on their PC. Maybe because this one is officially for Windows 10, mein is Windows 7(there is no official one for Windows 7), but there was no warning or whatsoever while the driver-installation and all SSDs and Harddrivers work fine. Anyway, after I uninstalled the driver and deleted "iaStorF" in registry editor, DMM works totally correctly. Now I just use the standard AHCI driver comes with Windows 7. For anyone who has the similar issue: you must delete "iaStorF" in registry editor manually after uninstalling the intel driver. Otherwise DMM still won’t release freed memory.

Thank you again for your prompt and useful reply!

Re: DMM doesn’t release memory in SCSI mode

Posted: Wed May 13, 2020 2:49 am
by support
We never thought the intel ahci driver would cause this problem. Maybe because it is not designed for Windows 7 as you think. Thank you sharing your solution here. I'm glad that the problem is solved now. :)