Copy Paste Stuttering and speed drops to Zero

Sometimes when i try to Copy Paste from my Server to my Gaming PC Both running windows 10 Pro 64bit
my server is running i5 3570k with 16 gb ram and my gaming PC i7 6700k and also 16 gb ram
the green bar will freeze at certain points for a second or 2 then jump forward and sometimes also the speed will drop suddenly to Zero for 10 or 20 seconds then continue
most of the time when coppying from my server to my gaming PC i dont have any problems at all
but sometimes i can have the freezing and speed droping to zero and then continue as i said
do you have any idea why ?
i checked the SMART data of all of the drives WD Red 4 tb on my Server No error everything is Normal
also the drives on my gaming PC Everything is Normal
im not running any raid at all every drive is independent

Paul Black said:

Hello @yafatana,
[1] I noticed that the file you are Copying is about 2+ GB. Do you have the same problem on a file that is ONLY a few MBs for example?
[2] What OTHER Processes do you have running, are they Memory / System hungry?
I hope this helps.

1-this problem will happen rarely today i tried to move many files but everything was Normal
yesterday it happened twice
2-Most of the Time the CPU on my Server is between 1 to 5 % load same as my Gaming PC

but also i have a question
can a behavior like this corrupt Source files i mean files on my Server ?

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Paul Black said:

Hello @yafatana,
[1] I noticed that the file you are Copying is about 2+ GB. Do you have the same problem on a file that is ONLY a few MBs for example?
[2] What OTHER Processes do you have running, are they Memory / System hungry?
I hope this helps.

i Forgot to say that this will Happen only when i move files from my Server to my Gaming PC
Never happened when moving files from my Gaming PC to my Server