Reasons for a low speed of a RAM disk

Started by target

target

Reasons for a low speed of a RAM disk   11 July 2020, 20:35

Can someone explain the speed reduction in RAM disk operation on dual-processor boards?

We have two machines with SSD and Windows10 PRO 64bit (the disk was switched during the test):

1. i7-3770 (Ivy Bridge) with 32Gb DDR3-1600 dual channel (at the exchange rate in memory according to AIDA64 in 23GB/sec)
- shows a read-write speed over 3GB/sec on RAM disk

2. server mother on the c602 chipset (s2600GZ) and two E5-2650 V2 (Ivy Bridge) with 64Gb ECC DDR3-1600 quad channel (at the exchange rate in memory according to AIDA64 in 74Gb/sec)
- shows the read-write speed of no more than 2.5GB/sec on RAM disk regardless of the memory allocation in the first or second node, or without selecting this check box

Why does the RAM disk show performance degradation at a higher memory speed on server board?
SoftPerfect Support forum - Andrew avatar image

Re: Reasons for a low speed of a RAM disk   11 July 2020, 21:28

We did observe similar behaviour on a new Xeon machine with ECC memory comparing to a regular mid-range laptop. Contrary to the expectations, RAM Disk performed better on the laptop than on the hi-end Xeon system. Not sure about the reason; could be the ECC memory or something else.

Would you be able to try a different product on your two systems (for example Imdisk) and let us know how it performs?
Nunakoy

Re: Reasons for a low speed of a RAM disk   11 May 2021, 11:59

Hi, yesterday I started trial testing SoftPerfect RAM Disk software. But any settings allow me to have only about 500MB/s speed in the disk.

What I do for testing: I have about 20-30 files 10GB in sum and copy them fist to the RAM disk and then I create a copy folder for the first folder. And what I see, the copying speed is only 480-540MB/s. The disk size is 256GB (I have enough RAM for that), file system NTFS (I tried exFAT also), and no success to increase it. The RAM modules type is 32GB 4Rx4 PC3L-12800L-11-12-C0, the server is Dell PowerEdge R820 (4 CPUs), RAM configured to work at 1333MHz.
SoftPerfect Support forum - Ann avatar image
Ann

Re: Reasons for a low speed of a RAM disk   11 May 2021, 12:08

To exclude the chance that this issue is caused by hardware or the operating system, would you be able to try a different RAM Disk product on your system, as suggested above, and let us know how it performs?
Nunakoy

Re: Reasons for a low speed of a RAM disk   11 May 2021, 13:15

Yes, you are right: the Imdisk behavior is the same. Its speed is 460Mb/s, even a bit slower than SoftPerfect RAM Disk.
What do you think, would you be able to find a solution for increasing RAM disk speed for servers?
SoftPerfect Support forum - Ann avatar image
Ann

Re: Reasons for a low speed of a RAM disk   11 May 2021, 13:21

We will run some tests with our Xeon-based machine in a few days to see if there is a way to improve the performance. In the meantime, would you be able to run CrystalDiskMark and PassMark PerformanceTest on your machine to compare?

Below are the test results from a modern laptop where our RAM Disk demonstrated speeds of 80-90% of the maximum rates from PassMark, but we are still interested in seeing a similar screen shot from your machine.

SoftPerfect support forum
Sergey

Re: Reasons for a low speed of a RAM disk   15 December 2021, 20:41

Hello.
I apologize for literacy - I use google translator.

I have the same RAMDisk low speed problem. My computer has 2 physical processors, each processor has 6 pieces of DDR3R (Registered) ECC RAM modules, total 12 pieces.

I tried to create one disk per space, tried to create small disks fixed in each node and collect interleaved Raid 0 using Windows OS. But the disk speed was 1900 ~ 2500 MB per second. The memory speed is clearly higher. I attached screenshots of testing. If necessary, I am ready to help with testing on my equipment.
The results of testing the use of programs ImDisk, Arsenal Image Mounter showed similar results.
Is it generally possible to fix this problem?


Aida test RAM

SoftPerfect support forum


Crystal Disk Mark Ram disk x2 (emulated HDD, RAID 0, static separate node)

SoftPerfect support forum


Crystal Disk Mark Ram disk x1 small size (not emulated HDD, static node)

SoftPerfect support forum


Crystal Disk Mark Ram disk x1 big size (not emulated HDD, not static node)

SoftPerfect support forum


Aida test Ram Disk x1 big size, read

SoftPerfect support forum


Aida test Ram Disk x1 big size, write

SoftPerfect support forum


Aida test Ram Disk x1 big size, Average Write Access

SoftPerfect support forum


Aida test Ram Disk x1 big size, Buffered Write

SoftPerfect support forum
SoftPerfect Support forum - Andrew avatar image

Re: Reasons for a low speed of a RAM disk   15 December 2021, 21:01

Sorry we don't really know the inner workings of RAM hardware.

Our RAM Disk relies on Windows Kernel API, so it's likely to show speeds close to other products'.

Do I understand correctly that you have tried SoftPerfect RAM Disk, imDisk and Arsenal Image Mounter and they all showed similar results?
Sergey

Re: Reasons for a low speed of a RAM disk   15 December 2021, 21:30

Yes, that's correct.
SoftPerfect Support forum - Andrew avatar image

Re: Reasons for a low speed of a RAM disk   16 December 2021, 10:45

In that case I am afraid we can't do anything. Since all RAM disk products exhibit similar performance, this slowdown may be caused by other drivers or Windows settings. There is also a chance of an antivirus interfering with disk I/O trying to find viruses in the test data.

I would advise to start identifying the bottleneck by turning off real-time virus monitor(s). Windows Defender is installed and turned on by default on Windows 10/11. You may also have a third-party antivirus enabled. If this doesn't help, try installing a new copy of Windows without any third-party drivers to see if that changes anything.

Alternatively, create a RAM disk with HDD emulation and run Performance Monitor against it. You would need to watch these parameters of PhysicalDisk when running an I/O speed test:

SoftPerfect support forum

Normally the queue length should be less than 1 and Disk/sec time should be all zero, meaning less than 1ms. Your numbers might suggest where the bottleneck is.

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