Poor performance of Source engine on AMDGPU or fglrx drivers

[blueskull]

I am experiencing very poor performance on my Linux machine. CS:CZ runs smoothly, Unigine Valley runs at a lower FPS, but at least it gives me 30 fps, despite it gives my 70 fps on Windows.
However, the 2 Source engine games I tried, HL2 and L4D2, run very sluggish. All animations are so so, but not too bad. Whenever I move my mouse or keyboard, it starts to freeze. In the meanwhile, FPS remains >=60.
I know I am running on a particularly awful CPU, but on the same CPU using Windows, I get super smooth experience on both games. I can even run HL2 smoothly on iGPU (i5-4250U) even under Linux.
I highly suspect it is due to bad GPU driver. Can anyone confirm that AMD driver is sluggish even with not very demanding games like HL2 or L4D2?
So far I've tried fglrx in 15.10 repo, Crimson 15 from binary and AMDGPU in 16.04 kernel, and the latter one is worse, but both 3 suck.

Here is the hardware list:
ASRock X99E ITX ac
Xeon E5-2603V3 (I use this CPU before E5V4 BIOS releases, I have a 2696V4 on my hand, but I do not want to risk frying it)
AMD R9 nano
32GB ECC 2400 RDIMM*2 (derated to 1600 due to limitation of CPU)

Once again, can anyone confirm that Source engine is not compatible with AMD drivers in Linux?

[Mechanical Menace]

The general consensus (at least on Phoronix) seems to be that the R9 Nano and Fury are terribly supported by both the Catalyst and open source drivers. Apparently both use the LLVM hacks for things that the GPU can and should handle so the CPU becomes a serious bottleneck. Unfortunately I can't personally confirm this as I don't have the card to test.

[botcrusher]

You can't really blame linux at all for this one. This is down to whatever team writes the linux version of the amd drivers. Sheer laziness when compared to the fact that Mac ( a unix based platform ) has adequate drivers...
Amd has long had openGL issues, no wait, spectacular flops with openGL on linux.

[Monkeh]

Not sure what shit happened in AMDGPU or fglrx, it simply won't work. What's more, it even won't give me smooth experience in a VirtualBox Win7, even the only software I use is Altium.
Goodbye Linux, you should stay in VMs and servers. So far I have 1 micro server and 2 RPis running Linux, as well as 1 VM, but I will still use Windows as my daily OS, with M$ telemetry addresses blocked and GWX disabled.

It's such a shame to lose a user who expects so little for free.

Oh. Wait.

[RGB255_0_0]

AMD's Linux support is atrocious. Always was even back in the ATi days. They will be better with Vulkan supported games.

[botcrusher]

I wouldn't count on it. Now that they have mantle, and the openGL guys now have vulkan.. Wellll, you see where I'm going.

[Mechanical Menace]

I wouldn't count on it. Now that they have mantle, and the openGL guys now have vulkan.. Wellll, you see where I'm going.

Vulkan IS what was Mantle. AMD donated what they had of Mantle to Khronos when they gave up on it and decided to get thoroughly behind (what was at the time) glNext.

EDIT:

AMD's Linux support is atrocious. Always was even back in the ATi days. They will be better with Vulkan supported games.

By it's very nature Vulkan is very hard to get up and running so for a lot of uses out of games it's not really worth it and GL will stay in use. The only way Vulkan will help with them is if the plan to have GL drivers run on top of Vulkan comes to fruition.

[botcrusher]

I didn't know they were quietly putting mantle in the corner...
If that is the case, well, rip DX, long live GL

[Mechanical Menace]

I didn't know they were quietly putting mantle in the corner...

It wasn't exactly quiet, pretty much everything I've seen from Khronos about Vulcan makes no secret that it's derived in no small part from Mantle and obviously AMDs Vulkan API page mentions that:

Developed by the Khronos Group, the same consortium that developed OpenGL®, Vulkan™ is a descendant of AMD’s Mantle, inheriting a powerful low-overhead architecture

Sorry I've been following Vulkan closely and am still trying to get something together using it.