Windows 95 default has a MaxMTU of 1500. That means that packets of
1500 bytes are sent over the Internet. Most routers on the internet have
a MaxMTU of 576. That means your 1500 byte packet is fragmented in 3 packets.
The original packet
The packets after fragmentation.
The grey parts are data.
The blue parts are headers and footers.
The red part of the last block is useless space.
With fragmentation the speed goes down because it generates a lot of
useless space. If you set your MaxMTU to 576 there will be less unwanted
fragmentation so speed goes up. So the suggested value for MaxMTU is 567.