What results you get for 4.2.2 at http://gtmetrix.com ?
On really powerful server I am getting E & C…
B and A
Before installing VIVAshop theme I was getting A and A.
Getting an F for defer parsing of javascript.
Summary
[color=#777777][font=Arial, Tahoma, Verdana, sans-serif][size=3] [size=6] B[/size]
[size=3]Page Speed Grade:[/size]
[color=#A1CA82]size=6[/size][/color]
[size=6]C[/size]
[size=3]YSlow Grade:[/size]
[color=#D2B338]size=6[/size][/color]
[size=3]Page load time: 4.34s
Total page size: 1.08MB
Total number of requests: 93[/size][/size][/font][/color]
[color=#777777][font=Arial, Tahoma, Verdana, sans-serif][size=3][size=3]v4.2.2 on VPS[/size][/size][/font][/color]
For what it's worth…I had scaled my store logo down to correct size (I think 15 x 15 px) and I saw a big change because it did not have to be scaled every time a page loaded.
I also did the same to my pics on homepage and other pages and jumped from a D to a B.
Sliders also take some time to load and may affect page performance.
I now get A & C