I just upgraded my Linux Mint Mate 18.3 installation to Linux Mint Mate 19, using the mintupgrade utility. It required some manual fixes, but all in all it went smooth.
Below the first UserBenchmark using Linux Mint 19 with updated qemu/kvm packages:
UserBenchmarks: Game 60%, Desk 76%, Work 67%
CPU: Intel Core i7-3930K – 86.8%
GPU: Nvidia GTX 970 – 58.5%
SSD: Red Hat VirtIO 140GB – 72.1%
HDD: Red Hat VirtIO 2.5TB – 87.1%
HDD: Red Hat VirtIO 2TB – 51.7%
RAM: QEMU 1x16GB – 77.3%
MBD: QEMU Standard PC (Q35 + ICH9, 2009)