SVN checkout speed issue

Hi Team!

We think there may be a bug, or a feature we don't understand:

When checking out a repository using TortoiseSVN on top of a Visual SVN
Server v3.6, running on Windows Server 2012R2, we notice that files with a
mime type set (usually application/octet-stream) download from the checkout
MUCH FASTER. For a repo with lots of mime types set (mostly
application/octet-stream, as mentioned), we see speeds around
1.5-3MByte/sec. For non-mime-typed files, it's capped at around 300kb/sec
max. If some files come through with mime types in the
slower-to-checkout-repo, the DL speed bursts up to 1.5-3MBytes/sec, as we
see in the faster repo.

This leads us to believe that SVN's underlying checkout logic is running
some mime type evaluation logic on files without mimetype set, and that the
logic ran is extremely inefficient or slow by design.

*1. is this a bug, or a feature by default?*
*2. can we disable the logic doing the mime type check for files without
mime type data, to speed up checkouts?*
*3. can we force SVN to see files without mime types set at text or binary,
to stop the logic that tries to figure out a file's mime type
programattically?*
*4. Any other input or feedback to help us? :)*

Screenshot attached for showing the differences in checkout speed we're
seeing.

*NOTE: *In the screenshot, we kicked off the checkouts at roughly the same
time; as you can see, the "zebitpaymentsystem" checkout is MUCH quicker,
averaging around 3x the checkout speed of the other repo. The other repo
has far far less mime types on the files in SVN, hence why we think it's
related.