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Strange SSD behavior!

Tags:
  • SSD
  • CPUs
  • Storage
Last response: in Storage
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January 25, 2013 2:36:10 AM

Hi, I'm just going to start with a picture:

http://screenshotuploader.com/i/01/6uu0lcv1h.png

Explanation:
The benchmarks on the left side are made while the CPU was not stressed, as in idle environment, but here's come the fun part because the benchmarks on the right side are made while the CPU was kept at 100% - by Everest's stress test (CPU) but it's not exclusive to Everest, any CPU hogging application will make the SSD faster.

So why is my SSD is faster in every test I tried when my CPU is stressed to 100%?

The SSD is a fresh Samsung 840 (non-Pro) and I have an Athlon II X2 3.4 @ 4.0 CPU and a fresh Win7 x64 HP.
I'm using amd_sata controller drivers (1.2.1.331). And my MB only supports Sata2.

Edit: This phenomenon applies to my other SSD too. (Silicon Power V20 40GB)
Edit2: Using the Standard AHCI Sata driver is the same and setting the minimum processor state to 100% (no lowering down to 800 mhz when idle) in the power options is not helping either.

More about : strange ssd behavior

a b G Storage
January 25, 2013 5:34:08 AM

you can try turning of power saving features in the BIOS, C1E and all the other stuff and test again.
January 25, 2013 5:53:09 AM

Tried that, no effect.
Related resources
January 25, 2013 10:20:24 PM

Any more ideas?
January 26, 2013 3:08:29 AM

Ok, I found the problem and the solution.

So apparently the CPU has more idle modes than I thought. In other words, the CPU can be idle even if it's not downclocking itself. Which is great, but some chipsets - like mine (AMD 880G/SB710) - is not "waking up" the CPU in case of heavy I/O operations.

So there's a registry key with which we can disable the cpu ever being idle by chaning the Attributes key from 1 to 0 under:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\PowerSettings\54533251-82be-4824-96c1-47b60b740d00\5d76a2ca-e8c0-402f-a133-2158492d58ad]

which unlocks an option in the Power Options which looks like this:



So with this option I have awesome speeds - for sata2 that is - but this option has some disadvantages as well. One of which is higher CPU temperatures, more power consumption because it appears disabling this idle state is acting like the CPU is at 100% but it is not, as you can see marked on the picture with red (cpu usage).
So if you have a dumb chipset and a CPU which gets hot under heavy load than it's not for you.
My CPU's idle temperature is around 30°C with stock cooler at 10% (ten) fan speed @4.0 (from 3.4) but with this "tweak" it's around 38°C.


Source: http://www.storagereview.com/how_to_improve_low_ssd_performance_in_intel_series_5_chipset_environments
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