Assuming the CAT5 plugs are terminated properly, you can probably get gigabit* up to 100 mtrs.
Also good to get solid cable, as opposed to stranded.
I have doubts about the first point ...
From reading, the OP used Infrastructure cable, which is solid, into RJ45 plus which are designed for patch cable (stranded).
If both network cards are Gbit capable then I would suggest the problem could be a dodgy connection or two.
You and I both know that the cable which is probably solid should be terminated in IDCs on te back of an RJ45 socket mounted on a standard faceplate. Then patch leads from the socket to router or PC.
It is also (as you know) bad practice to install fixed cable in a non-standard way. They should be straight through and the cross over done in the flying/patch lead. How many times have I seen problems in wiring where something like that has been done.
M H C
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