Windows 10 October 2018 Update rollout now paused

lx07 · 17 Oct 2018

kado897 said:

My understanding is that it is done to save disk space at the expense of performance as I said earlier I wish I knew what informed the decision.

I did quite a lot of testing on this and found that for me compression increased performance by varying amounts.

Whether it will for you depends on the relative speed of your ssd vs your processor. If your ssd is slow and cpu fast you'll see more benefit while if you have fast disk and slow cpu you will not. I imagine this is the sort of conditions it checks but idk.

You can try it - if it is worse for you then you can turn it off again as per the tutorial in Bree's post above.

Bree · 17 Oct 2018

lx07 said:

Whether it will for you depends on the relative speed of your ssd vs your processor...

Mine has an HDD, not an SSD.

Wiley Coyote · 17 Oct 2018

Humph! So much for my "blissful ignorance". I'm setting here with a 1 TB HDD that's got 852 GB free and 12 GB of ram. Must be one of those things where MS knows what's best for me, whether I do or not.

lx07 · 17 Oct 2018

Bree said:

Mine has an HDD, not an SSD.

I found compression on HDD improved performance too. In fact it got more of a benefit than SSD although both were faster with compression on. I couldn't compare differing RAM amounts as all my PC have the same 8GB.

kado897 · 17 Oct 2018

lx07 said:

I found compression on HDD improved performance too. In fact it got more of a benefit than SSD although both were faster with compression on. I couldn't compare differing RAM amounts as all my PC have the same 8GB.

That makes sense as you are reading less from disk.

CountMike · 17 Oct 2018

Hmmmm:

Windows 10 October 2018 Update rollout now paused-image.png

How to change it ?

kado897 · 17 Oct 2018

CountMike said:

Hmmmm:

How to change it ?

Compress or Uncompress Windows 10 with Compact OS

Bree · 17 Oct 2018

CountMike said:

How to change it ?

From a command prompt (admin) using compact /compactos:<option>

 /CompactOs Set or query the system's compression state. Supported options are:

query - Query the system's Compact state.

always - Compress all OS binaries and set the system state to Compact

which remains unless administrator changes it.

never - Uncompress all OS binaries and set the system state to non

Compact which remains unless administrator changes it.

cereberus · 17 Oct 2018

kado897 said:

Not mine. I wonder what informs the decision.

Attachment 208762

It is actually very simple - it should only invoke CompactOS on small drives e.g. 32GB mmc drives. On anything much larger (cannot remember cutoff point), it does not use Compact OS. You can manually invoke it but there is a tradeoff between space saved and decompression time.

cereberus · 17 Oct 2018

lx07 said:

I did quite a lot of testing on this and found that for me compression increased performance by varying amounts.

Whether it will for you depends on the relative speed of your ssd vs your processor. If your ssd is slow and cpu fast you'll see more benefit while if you have fast disk and slow cpu you will not. I imagine this is the sort of conditions it checks but idk.

You can try it - if it is worse for you then you can turn it off again as per the tutorial in Bree's post above.

I am pretty sure it only checks for size of hard drive and if under a certain size, it invokes CompactOS. It's primary function is simply to reduce storage requirements on devices with limited storage e.g. 32GB mmc drives.

It was never intended to optimise the OS in the way you describe. It just SO HAPPENS in some cases, you might get a gain in performance e.g. slow hdd and fast CPU as you say. If you could go to the limit and had Windows in a RAMDISK, the CompactOS would actually slow down the PC unless the CPU was blindingly fast as well.

As an aside, I recommend keeping CompactOS off unless necessary, as you can get issues recovering data e.g. mobo has failed, and you put drive in another PC. The interaction with Bitlocker has caused people issues iirc.