Does MKV behave differently than AVI

I am a novice to this whole experience of streaming my vid and pic files to TV, I know nothing technical yet.
I realize there are similar posts, but I couldn't find a definitive answer.

Do any of you experience these issues

Often only lasting about 5-10 minutes before starting into jerky playback and eventually stopping 10-12 seconds between pauses making it unviewable.

I noticed when I shut the BD player down and restart it, the playback seems to buffer faster and provides better performance (even with AVI) but with MKV, eventually fails all-together

I converted my MKV's to AVI format to see if it made a difference. In some cases it did, but for the better part, the files were still large and playback was eventually interrupted.
I can't make it through a whole movie without having to restart BD player at least once.
Should I be converting to a lower format quality file in order to achieve better playback, I really hate sacrificing quality.

Are there things I can do to improve the performance of the devices whether its the computer, router or BD player to help improve the performance of MKV playback.

[zip]

you didn't give any detail about your setup (PC, router, network setup, player)

Thanks, I did have that listed before but thought it was too much information then removed it.
I thought maybe there are some standard settings that I should consider.

I run two Samsung C6900 series BD players over a wireless Cisco N router about 20 feet away from two computer servers.
One running Vista the other running Win 7 both 64bit OS
Each computer has an Intel quad core processor with 8 gig RAM clocking at around 3.2g ghz

The issues I'm having are related to large files like my MKV's.
When I convert them to AVI's it improves the performance but still get some shuddering.
I try to retain the quality of my videos so the files are still rather large.

Any standard 700-800mb file seems to run fine, but the 5-6gig files give me trouble.
I thought maybe there was a buffer that could be configured to process faster or with more efficiency.

Oh, I just realized that in the browser you can view the resolution of files, I didn't see this before.
The 720x480 files have no issues but the ones going at 1280 have issues. I also noticed that they don't appear on the Serviio browser .

I'm still impressed with everything so far, just learning the limitations.

[zip]

try to connect the PC and the TV to the router with wires to eliminate the wireless connection