It artifacts the framebuffer at KMS, i had to use nomodeset as kernel parameter to work around. Xorg is stuck on 640x480 and it can't use OpenGL 1.2 either.

lspci -vvnnk

01:00.0 VGA compatible controller [0300]: NVIDIA Corporation NV4 [Riva TNT] [10de:0020] (rev 04) (prog-if 00 [VGA controller])
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
	Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 64 (1250ns min, 250ns max)
	Interrupt: pin A routed to IRQ 11
	Region 0: Memory at f8000000 (32-bit, non-prefetchable) [size=16M]
	Region 1: Memory at fc000000 (32-bit, prefetchable) [size=16M]
	[virtual] Expansion ROM at 000c0000 [disabled] [size=128K]
	Capabilities: [60] Power Management version 1
		Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
		Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
	Capabilities: [44] AGP version 1.0
		Status: RQ=16 Iso- ArqSz=0 Cal=0 SBA+ ITACoh- GART64- HTrans- 64bit- FW- AGP3- Rate=x1,x2
		Command: RQ=1 ArqSz=0 Cal=0 SBA- AGP- GART64- 64bit- FW- Rate=<none>
	Kernel modules: nouveau

glxheads

  Display:     0xa01d20
  Window:      0xc00002
  Context:     0xa15950
  GL_VERSION:  3.1 Mesa 19.0.5
  GL_VENDOR:   VMware, Inc.
  GL_RENDERER: llvmpipe (LLVM 8.0, 128 bits)