I'd never heard of this before, so shame on me, but programs like UPX can compress my files by 80% which is totally sweet, but I have no idea what the the disadvantages are in doing this. Or even what the compressor does.

• ^{Website linked above doesn't say anything about dynamically linking DLLs but it mentions about compressing DESCENT 2 and about compressing Netscape 4.06. Also, it doesn't say what the tradeoffs are, only the benefits. If there weren't tradeoffs why wouldn't my linker compress the file?}

If I have an environment where I have one executable and 20-30 DLL's, some of which are dynamically loaded an unloaded fairly arbitrarily, but not in loops (hopefully), do I take a big hit in processing time decompressing these DLL's when they're used?