CrystalDiskMark 'Run as administrator' increases benchmark speeds

[Abom]

The image below includes further details. Also, disabling UAC in Win10 (not recommended) produces the same result when running CrystalDiskMark normally.

Anyone know why there are such noticeable benchmark improvements in the 4KiB runs with ‘Run as administrator’ selected?

 

Bigger question: Does UAC throttle drive speeds?

 

Thanks!

[Tabs]

To answer your bolded question: No, UAC itself does not affect drive performance, since it only triggers on application launch or elevation request, it's not an always-running service like an antivirus or security software.

 

This could be a quirk with scheduling - it's possible that Windows prioritises disk access for programs with elevation, or it's possible that when running as an administrator it's setting itself to have high priority IO, which might be a function that requires elevation.

 

I'm honestly not sure, but I'd be interested to find out if other people experience this. Check the IO priority in Resource monitor under both scenarios to see if there's any change.

[Abom]

Thanks for the reply.

I/O Priority is 'Normal' when 'Running as administrator' and without.

 

What's interesting is very rarely I can get the benchmark running normally to produce the higher result, say 1 in 20, but as Admin the higher results are consistent.

User reviews have a mix of both results. Tech site reviews consistently show the higher results.

[Syntaxvgm]

4k seems to be whats affected, sequential is margin of error. 

I think it would have to do with task priority or something. The first result is non administrator on a laptop, the second with with elevation, and both results are very consistent. I only did one section becuase I didn't have time for all of them right now. 

I've noticed this and I've always elevated games for this reason, somethings up with scheduling or something, but idk what it is. The result is not changed with assigning priority. 

Perhaps someone on here can explain why windows does this. 
Non elevated 

Elevated

[Mira Yurizaki]

I'm going to guess it has something to do with the security system in Windows, since the "Run as Administrator" command basically gives you unrestricted access and therefore, may skip certain checks. Note that the sequential tests are the same, but the 4K tests are not. As the 4K tests are multiple requests to the dummy file CrystalDiskMark creates, that requires multiple checks to the file system to make sure you still have access to the file.

[Abom]

Updated benchmark comparison after down rev to pre-Spectre/Meltdown BIOS