The purpose of GZIP: This causes pages to be compressed before being transmitted from server to browser, making the transmitted data smaller, thus speeding delivery.
However, if PHP is already configured on the server to have "output_buffering" turned on (ie: set to "on" or "1"), then it's already doing this compression before transmission, and if you turn on GZip compression in Zen Cart, you're potentially forcing it to be done twice, which is redundant and actually can slow things down.
GZip is most likely not the issue for your current server.
It's most likely a poorly-tuned MySQL engine which doesn't have enough RAM allocated to it and therefore cannot do enough caching or query buffering to offer speedy performance with Zen Cart's required queries.
(Before someone goes off on a tirade of saying Zen Cart uses too many queries, don't. v1.4.0 currently in development has dropped queries drastically, which will certainly help in cases such as this. But that's future.)
In short, add lotsa ram and allocate it strategically so that the server has sufficient resources to run efficiently.
If this is a server you have no control over, try a different host which already manages the server with optimization in mind.
.
Zen Cart - putting the dream of business ownership within reach of anyone!
Donate to: DrByte directly or to the Zen Cart team as a whole
Remember: Any code suggestions you see here are merely suggestions. You assume full responsibility for your use of any such suggestions, including any impact ANY alterations you make to your site may have on your PCI compliance.
Furthermore, any advice you see here about PCI matters is merely an opinion, and should not be relied upon as "official". Official PCI information should be obtained from the PCI Security Council directly or from one of their authorized Assessors.
