Firefox has alaways been slow on my intel ivybridge celeron ( ubuntu 14.04) and here is what I get from the about:support How could I activate the GPU acceleration ? it works on Chrome. Graphics Adapter Description Intel Open Source Technology Center -- Mesa DRI Intel(R) Ivybridge Mobile Device ID Mesa DRI Intel(R) Ivybridge Mobile Driver Version 3.0 Mesa 10.1.3 GPU Accelerated Windows 0/1 Basic Vendor ID Intel Open Source Technology Center WebGL Renderer Intel Open Source Technology Center -- Mesa DRI Intel(R) Ivybridge Mobile windowLayerManagerRemote false AzureCanvasBackend cairo AzureContentBackend cairo AzureFallbackCanvasBackend none AzureSkiaAccelerated 0