sync-standard-vs-disabled KVM testing on Debian 8.7 via the Phoronix Test Suite. test-kvm-sync-disabled: Processor: Common KVM @ 2.40GHz (2 Cores), Motherboard: QEMU Standard PC (i440FX + PIIX 1996), Chipset: Intel 440FX- 82441FX PMC, Memory: 2048MB, Disk: 32GB, Graphics: Cirrus Logic GD 5446, Network: Red Hat Virtio device OS: Debian 8.7, Kernel: 3.16.0-4-amd64 (x86_64), Compiler: GCC 4.9.2, File-System: ext4, System Layer: KVM test-kvm-sync-standard: Processor: Common KVM @ 2.40GHz (2 Cores), Motherboard: QEMU Standard PC (i440FX + PIIX 1996), Chipset: Intel 440FX- 82441FX PMC, Memory: 2048MB, Disk: 32GB, Graphics: Cirrus Logic GD 5446, Network: Red Hat Virtio device OS: Debian 8.7, Kernel: 3.16.0-4-amd64 (x86_64), Compiler: GCC 4.9.2, File-System: ext4, System Layer: KVM SQLite 3.8.10.2 Test Target: Default Test Directory Seconds < Lower Is Better test-kvm-sync-disabled . 10.18 | test-kvm-sync-standard . 1582.05 |============================================= Threaded I/O Tester 0.3.3 Test: Random Read - Size Per Thread: 64MB - Thread Count: 32 MB/s > Higher Is Better test-kvm-sync-disabled . 839.13 |============================================== test-kvm-sync-standard . 817.15 |============================================= Threaded I/O Tester 0.3.3 Test: Random Write - Size Per Thread: 64MB - Thread Count: 32 MB/s > Higher Is Better test-kvm-sync-disabled . 185.26 |============================================== test-kvm-sync-standard . 0.51 | Apache Benchmark 2.4.7 Static Web Page Serving Requests Per Second > Higher Is Better test-kvm-sync-disabled . 6176.05 |============================================= test-kvm-sync-standard . 6243.43 |=============================================