ISLC and its impact on memory

[Parisien_entraide]

Hello

After various tests with LatencyMon, both with and without ISLC, I noticed that it causes me to lose memory bandwidth in the MOC test (I’m not providing the link because I don’t want to be considered a spammer).

On the other hand, I do see some benefits elsewhere. For example, the usual Nvidia driver no longer appears as the main source in LatencyMon (2-minute-30-second test).

---------------------------------------------------With --------------Without ISLC---------------Différence

Read ------------------------------------------ 56,1 Go/s-----------72,5 Go/s---------------+29 % sans ISLC

Write ------------------------------------------67,0 Go/s---------- 81,2 Go/s ---------------+21 % sans ISLC

Copy -------------------------------------------34,9 Go/s-----------37,9 Go/s-----------------+9 % sans ISLC


This board : With ISLC - Without ISLC - Withou ILSC but with the program "Timer Resolution" (0.500ms)

tableau_comparatif_latencyMon.png

There was no Standby List cleanup. Here is my ISLC configuration:

Performance Timer: TSC (Synthetic 10 MHz)
Current Timer Resolution: 0.504 ms
Maximum Timer Resolution: 0.5 ms
Minimum Timer Resolution: 15.625 ms
Desired Timer Resolution: 0.5046 ms (set manually following the test from TimerResBenchmark)

The following options are enabled in ISLC:

Enable custom timer resolution
Use GlobalTimerResolutionRequest


HPET

uselegacyapicmode No
useplatformclock No
useplatformtick Yes
disabledynamictick Yes




CONTEXT

My configuration

- MSI Z890P P WiFi (everything is up to date; BIOS and drivers from MSI sources)
- CPU: i7-265KF
- RAM: 32 GB DDR5 Corsair Vengeance CMH32GX5M2B6000C38, 6000 MHz, CL38 with XMP (38-44-44-96-140)
Intel 200S Boost enabled, as well as the new RAM Performance Mode
“This memory extension mode optimizes DDR5 sub-timings, reduces latency, and increases performance by up to 14%” (MSI source), depending on the profile. I selected the High Efficiency profile, which is the maximum setting.
For example, the tRFC setting changes from 480 (idle) to 140 under load (the maximum supported by the RAM), depending on the Bitsum ParkControl profile.
I’m using the Intel-recommended default settings for PL1 / PL2.
- Everything is managed by Intel’s AI NPU.
- Microsoft Windows 11 Professional (x64) 25H2 Build 26200.9168, fully up to date
- WD_BLACK SN8100 2 TB PCIe 5.0, installed in a PCIe 5.0 slot
- Nvidia RTX 5070Ti 16GB
- HAGS enabled, MPO, etc.

- I use reliable tweaking tools such as WinHance (I’m aware of the impact of the modifications I make).

In all of my tests, I experienced no crashes or instability, including while gaming.

---------------

Edit : Interessant...

https://randomascii.wordpress.com/2020/ ... le-change/
https://learn.microsoft.com/en-us/windo ... eginperiod

[Wagnard]

Hello

After various tests with LatencyMon, both with and without ISLC, I noticed that it causes me to lose memory bandwidth in the MOC test (I’m not providing the link because I don’t want to be considered a spammer).

On the other hand, I do see some benefits elsewhere. For example, the usual Nvidia driver no longer appears as the main source in LatencyMon (2-minute-30-second test).

---------------------------------------------------With --------------Without ISLC---------------Différence

Read ------------------------------------------ 56,1 Go/s-----------72,5 Go/s---------------+29 % sans ISLC

Write ------------------------------------------67,0 Go/s---------- 81,2 Go/s ---------------+21 % sans ISLC

Copy -------------------------------------------34,9 Go/s-----------37,9 Go/s-----------------+9 % sans ISLC


This board : With ISLC - Without ISLC - Withou ILSC but with the program "Timer Resolution" (0.500ms)
tableau_comparatif_latencyMon.png




There was no Standby List cleanup. Here is my ISLC configuration:

Performance Timer: TSC (Synthetic 10 MHz)
Current Timer Resolution: 0.504 ms
Maximum Timer Resolution: 0.5 ms
Minimum Timer Resolution: 15.625 ms
Desired Timer Resolution: 0.5046 ms (set manually following the test from TimerResBenchmark)

The following options are enabled in ISLC:

Enable custom timer resolution
Use GlobalTimerResolutionRequest


HPET

uselegacyapicmode No
useplatformclock No
useplatformtick Yes
disabledynamictick Yes




CONTEXT

My configuration

- MSI Z890P P WiFi (everything is up to date; BIOS and drivers from MSI sources)
- CPU: i7-265KF
- RAM: 32 GB DDR5 Corsair Vengeance CMH32GX5M2B6000C38, 6000 MHz, CL38 with XMP (38-44-44-96-140)
Intel 200S Boost enabled, as well as the new RAM Performance Mode
“This memory extension mode optimizes DDR5 sub-timings, reduces latency, and increases performance by up to 14%” (MSI source), depending on the profile. I selected the High Efficiency profile, which is the maximum setting.
For example, the tRFC setting changes from 480 (idle) to 140 under load (the maximum supported by the RAM), depending on the Bitsum ParkControl profile.
I’m using the Intel-recommended default settings for PL1 / PL2.
- Everything is managed by Intel’s AI NPU.
- Microsoft Windows 11 Professional (x64) 25H2 Build 26200.9168, fully up to date
- WD_BLACK SN8100 2 TB PCIe 5.0, installed in a PCIe 5.0 slot
- Nvidia RTX 5070Ti 16GB
- HAGS enabled, MPO, etc.

- I use reliable tweaking tools such as WinHance (I’m aware of the impact of the modifications I make).

In all of my tests, I experienced no crashes or instability, including while gaming.

---------------

Edit : Interessant...

https://randomascii.wordpress.com/2020/ ... le-change/
https://learn.microsoft.com/en-us/windo ... eginperiod

I suspect the timer resolution, try without the timer resolution set. Technically a higher resolution(<1ms) is more demanding. If its not helping the bandwidth, try changing the polling rate to a way longer one to see if it help. Maybe polling too often the memory is causing this.